| acceleration of reproductive development in female djungarian hamsters by adult males. | housing young female djungarian hamsters (phodopus campbelli) with an adult male accelerates uterine and ovarian development and there is a strong relationship between uterine weight and ovarian measures (e.g., follicular size). uterine weights of females housed with an adult male for 10 days following weaning are comparable to values from females housed alone for 25 days. removal of endogenous androgens by castration eliminated the capacity of adult males to accelerate reproductive development ... | 1988 | 3413251 |
| cyclic djungarian hamsters, phodopus campbelli, lack the progesterone surge normally associated with ovulation and behavioral receptivity. | serum levels of 17 beta-estradiol and progesterone were assayed at 4- to 5-h intervals across the estrous cycle in female djungarian hamsters, phodopus campbelli. the pattern of secretion for estradiol is similar to that described for the rat and the syrian hamster, rising slowly from a baseline of 54 +/- 2 pg/ml during the morning of estrus to a peak of 187 +/- 16 pg/ml in the early afternoon of proestrus, then falling rapidly back to baseline levels. the pattern of progesterone secretion is si ... | 1987 | 3830052 |
| goblet cell mucins of four genera of the subfamily cricetinae with reference to the protective activity against strongyloides venezuelensis. | goblet and mast cell responses in the jejunum of four genera, mesocricetus auratus (syrian hamster), phodopus campbelli, cricetulus griseus (chinese hamster), and tscherskia triton, belonging to the subfamily cricetinae, were examined after infection with strongyloides venezuelensis. parasite eggs became detectable in faeces of all four genera on day 7. faecal egg count peaked around day 8 in c. griseus and t. triton and around day 14 in m. auratus and p. campbelli. in m. auratus and p. campbell ... | 1994 | 7870465 |
| novel patterns of progesterone and prolactin in plasma during the estrous cycle in the djungarian hamster (phodopus campbelli) as determined by repeated sampling of individual females. | in contrast to results from previous research, a surge of progesterone (p4) on the afternoon of proestrus was consistently detected in djungarian hamster females. however, the timing of maximal p4 levels varied from 1200 to 1900 h across females; this impeded detection of the surge in earlier studies. no role for p4 in the induction of behavioral receptivity was found. behavioral receptivity was induced in ovariectomized females with physiological levels of estradiol typical of an estrous cycle ... | 1996 | 8924501 |
| reproductive aging in the djungarian hamster, phodopus campbelli. | changes in fertility (delivery success), fecundity (litter size and weaning success), sensitivity to pregnancy-blocking stimuli (mate removal after 24 h), and hypothalamic-pituitary-ovarian function were assessed during reproductive aging in the djungarian hamster, phodopus campbelli. all indices of aging occurred earlier in the djungarian hamster than they do in other laboratory models, including the mouse. fertility and fecundity were halved by 8 mo of age, and the response to pregnancy-blocki ... | 1998 | 9510975 |
| divergent reproductive endocrinology of the estrous cycle and pregnancy in dwarf hamsters (phodopus). | progesterone (p4) and prolactin (prl) in peripheral circulation of siberian hamsters (phodopus sungorus) throughout an estrous cycle and pregnancy were determined by repeated, small volume sampling from individuals housed in modified home cages. as predicted, the endocrinology of p. sungorus reproduction is similar to the rat, mouse and golden hamster and shows none of the eight distinctive features known for djungarian hamsters (phodopus campbelli). specifically, in p. sungorus there is no evid ... | 1999 | 10605068 |
| predator odour and its impact on male fertility and reproduction in phodopus campbelli hamsters. | this study investigated the influence of cat urine odour in suppressing development and fertility in campbell's hamster males. exposure to this odour from postnatal day 11 until day 45 (sexual maturation) resulted in reduced sex organ weights, reduced testosterone levels and in an increase in abnormalities of the synaptonemal complex in both sex chromosomes and autosomes. subsequent breeding experiments revealed a significant decrease in litter size. all these data indicate a severe effect of pr ... | 2000 | 11013879 |
| social transmission of flavor preferences in two species of hamsters (mesocricetus auratus and phodopus campbelli). | golden hamsters (mesocricetus auratus) and dwarf hamsters (phodopus campbelli) interacted with a conspecific demonstrator that had recently consumed a flavored food. when given a choice between their demonstrator's flavor and another flavor, the dwarf hamsters preferred the flavor their demonstrator had eaten. golden hamsters did not prefer their demonstrators' diets when the demonstrators were unrelated adults or littermates, but they did when the demonstrator was their mother. videotaping the ... | 2003 | 14717647 |
| [microbacterium oxydans, a symbiont of djungarian hamster, displaying probiotic properties]. | a resident microorganism (strain kho-17) was isolated from secretions of the specific glandular structures at the angles of mouth of djungarian hamster (phodopus campbelli). according to cultural, morphological, and physiological properties as well as to the phylogenetic analysis basing on the sequences of 16s rrna gene and analysis of the cell wall the strain was assigned to the species microbacterium oxydans. the bacterium isolated displayed probiotic properties when administered orally as a s ... | 2004 | 15609853 |
| phodopus campbelli detect reduced photoperiod during development but, unlike phodopus sungorus, retain functional reproductive physiology. | golden (mesocricetus auratus) and siberian (phodopus sungorus) hamsters are widely used as animal models for seasonal reproduction; but m. auratus shows no developmental delay in short days until after sexual maturity, whereas p. sungorus juveniles delay development in short days. as the photoperiodic response of phodopus campbelli is not well established, litters of the two phodopus species were gestated and reared under long days (14 h light:10 h darkness) or short days (10 h light:14 h darkne ... | 2006 | 17008477 |
| paternal care in rodents: weakening support for hormonal regulation of the transition to behavioral fatherhood in rodent animal models of biparental care. | male rodents that are naturally paternal, like all females, must inhibit infanticide and activate direct parental behavior as they become parents. males, however, alter their behavior in the absence of parturition, postpartum ovulation and lactation, and therefore do not experience the hormone dynamics associated with such conditions. paternal males might nevertheless use the same hormones to activate pre-existing maternal behavior pathways in the brain. positive and inverse associations between ... | 2007 | 17482188 |
| dwarf and golden hamsters' differing responses to conspecific signals for food. | the author presented dwarf hamsters (phodopus campbelli) and golden hamsters (mesocricetus auratus) with conspecific and inanimate signals for food. both species approached a cardboard stimulus that predicted food. the dwarf hamsters engaged in high levels of social contact directed toward a conspecific conditioned stimulus for food, but the golden hamsters did not. the author also presented dwarf hamsters with a conspecific signal that did not indicate food, and the levels of social behaviors t ... | 2008 | 18318408 |
| cryptosporidium spp. in wild, laboratory, and pet rodents in china: prevalence and molecular characterization. | to understand the prevalence of cryptosporidium infection in rodents in china and to assess the potential role of rodents as a source for human cryptosporidiosis, 723 specimens from 18 rodent species were collected from four provinces of china and examined between august 2007 and december 2008 by microscopy after using sheather's sugar flotation and modified acid-fast staining. cryptosporidium oocysts were detected in 83 specimens, with an overall prevalence of 11.5%. phodopus sungorus, phodopus ... | 2009 | 19820152 |
| novel rodent models for macular research. | many disabling human retinal disorders involve the central retina, particularly the macula. however, the commonly used rodent models in research, mouse and rat, do not possess a macula. the purpose of this study was to identify small laboratory rodents with a significant central region as potential new models for macular research. | 2010 | 20976212 |
| [the development of the pouch-like structures at the angles of the mouth in the ontogeny of the hamster phodopus campbelli]. | the development of mouth angle sacciform structure was studied in the ontogenesis of hamster phodopus campbelli. it was found that the true sacciform structure with all components characteristic for adult animals was formed by the 20th day of postnatal development. histological data have shown than the sacciform structure is formed in ontogenesis as a result of a complex epidermal transformation involving muscular and connective tissues which comprise the external coat. the structure studied is ... | 2006 | 1447419 |
| survey of hymenolepis spp. in pet rodents in italy. | we carried out the first survey of hymenolepis spp. infection in pet rodents in italy. fresh fecal samples were collected from 172 pet rodents as follows: guinea pigs (cavia porcellus; n = 60), squirrels (callosciurus finlaysonii, callosciurus prevosti, tamias striatus, tamias sibiricus, sciurus calorinensis; n = 52), hamsters (phodopus campbelli, mesocricetus auratus; n = 30), chinchillas (chinchilla lanigera; n = 13), rats (rattus norvegicus; n = 10), and mice (mus minutoides; n = 7). these an ... | 2015 | 26290218 |
| behavioral responses of predator-naïve dwarf hamsters (phodopus campbelli) to odor cues of the european ferret fed with different prey species. | many mammalian predators are able to identify their prey by odors and, vice versa, numerous prey species recognize predator odors as well. the present paper reports on the behavioral responses of predator-naïve dwarf hamsters (phodopus campbelli) towards the urine odors of carnivorous ferrets, which were raised on either a chicken, mouse or hamster diet. chemical composition from ferret urines of the different diet groups was analyzed, while quantitative differences in urinary volatile constitue ... | 2015 | 26066723 |
| a comparative study of rodent ultrasonic vocalizations during copulation. | the temporal patterning of ultrasonic vocalizations (usvs) during copulation was recorded for male-female pairs of djungarian hamsters (phodopus campbelli), prairie voles (microtus ochrogaster), and montane voles (microtus montanus). each species appears to utilize a single major frequency band for usvs, centered around 31 khz for the vole species and 71 khz for hamsters. djungarian hamsters exhibited low rates of usvs prior to introduction of the female and following ejaculation, but a high usv ... | 1989 | 2649070 |
| in three brain regions central to maternal behaviour, neither male nor female phodopus dwarf hamsters show changes in oestrogen receptor alpha distribution with mating or parenthood. | oestrogen receptor (er)alpha immunoreactivity in three brain regions relevant to maternal behaviour (medial preoptic area, bed nucleus of the stria terminalis and medial amygdala) was measured in two species of dwarf hamster that both mate during a postpartum oestrous but differ in expression of paternal behaviour. male and female phodopus campbelli and phodopus sungorus were sampled as sexually naive adults, following mating to satiety, and as new parents. in all brain regions, females expresse ... | 2008 | 19094078 |
| [testosterone and induced humoral immunity in male campbell dwarf hamsters (phodopus campbelli, thomas, 1905, rodentia, cricetidae): experimental manipulation of testosterone levels]. | in this paper we report the results of testosterone manipulation in the blood of male campbell dwarf hamsters phodopus campbelli thomas, 1905 through castration, followed by testosterone treatment. under these conditions, we studied antibody production rates in response to injection with sheep red blood cells (srbc). it was shown that castration induced a dramatic decrease in blood testosterone but had no effect on the humoral response to srbc. males that received a testosterone compound with a ... | 2016 | 26349233 |
| bilateral hydronephrosis with urinary tract infection in a campbell's hamster (phodopus campbelli). | | 2015 | 25908333 |
| abnormal pairing of x and y sex chromosomes during meiosis i in interspecific hybrids of phodopus campbelli and p. sungorus. | hybrid sterility plays an important role in the maintenance of species identity and promotion of speciation. male interspecific hybrids from crosses between campbell's dwarf hamster (phodopus campbelli) and the djungarian hamster (p. sungorus) exhibit sterility with abnormal spermatogenesis. however, the meiotic phenotype of these hybrids has not been well described. in the present work, we observed the accumulation of spermatocytes and apoptosis of spermatocyte-like cells in the testes of hybri ... | 2015 | 25801302 |
| [immunocompetence and reproductive characteristics of male campbell dwarf hamsters selected for low and high humoral immune response to srbc: testing the immunocompetence handicap hypothesis]. | we selected campbell dwarf hamsters (phodopus campbelli thomas, 1905) for low and high humoral immune response to the sheep red blood cells (srbc) challenge in three generations (p, f1, f2). non-specific innate immunity and acquired t-cell immunity, resting metabolic rate, testosterone, and cortisole hormone levels, reproductive characteristics, including maturation related morphological traits, and aggressive behavior were studied within sets of males:with low (li) and high (hi) immune response ... | 2015 | 25782275 |
| adapting to alcohol: dwarf hamster (phodopus campbelli) ethanol consumption, sensitivity, and hoard fermentation. | ethanol consumption and sensitivity in many species are influenced by the frequency with which ethanol is encountered in their niches. in experiment 1, dwarf hamsters (phodopus campbelli) with ad libitum access to food and water consumed high amounts of unsweetened alcohol solutions. their consumption of 15%, but not 30%, ethanol was reduced when they were fed a high-fat diet; a high carbohydrate diet did not affect ethanol consumption. in experiment 2, intraperitoneal injections of ethanol caus ... | 2015 | 25712038 |
| embryo cryopreservation and in vitro culture of preimplantation embryos in campbell's hamster (phodopus campbelli). | the aims of this study were to compare different protocols of campbell's hamster (phodopus campbelli) embryos freezing-thawing and to explore the possibilities of their in vitro culture. first, the embryos were flushed from the reproductive ducts 2 days post coitum at the two-cell stage and cultured in rat one-cell embryo culture medium (r1ecm) for 48 hours. most (86.7%) of the two-cell embryos developed to blastocysts in r1ecm. second, the embryos at the two- to eight-cell stages were flushed o ... | 2015 | 25583223 |
| effects of mitochondria-targeted plastoquinone derivative antioxidant (skq1) on demography of free-breeding campbell dwarf hamsters (phodopus campbelli) kept in outdoor conditions. reproduction and lifespan: explanation in the framework of ultimate loads. | we studied demographic effects of the mitochondria-targeted antioxidant skq1 on free-breeding campbell dwarf hamsters (phodopus campbelli, thomas, 1905, rodentia, cricetidae) in an outdoor vivarium with seasonally varying day length and temperatures. the animals were kept in pairs from their young age. we removed litters from parental cages at their age of 25 days. experimental hamsters received daily 50 nmol/kg skq1 with water by oral dosing, whereas control animals received water. skq1 had no ... | 2014 | 25519070 |
| mitochondria-targeted antioxidant skq1 accelerates maturation in campbell dwarf hamsters (phodopus campbelli). | we tested two hypotheses. 1) skq1 positively affects postnatal development of hamsters in litters born to parents receiving long-term skq1 treatment. 2) skq1 accelerates maturation of juvenile females receiving the antioxidant treatment from 10 days of age. parental pairs were kept in an outdoor vivarium under conditions close to natural. at the age of 25 days, juvenile males in litters born to parents treated daily with skq1 (50 nmol/kg per os) had higher epididymis mass. both the size of a lit ... | 2014 | 25519069 |
| parent-of-origin growth effects and the evolution of hybrid inviability in dwarf hamsters. | mammalian hybrids often show abnormal growth, indicating that developmental inviability may play an important role in mammalian speciation. yet, it is unclear if this recurrent phenotype reflects a common genetic basis. here, we describe extreme parent-of-origin-dependent growth in hybrids from crosses between two species of dwarf hamsters, phodopus campbelli and phodopus sungorus. one cross type resulted in massive placental and embryonic overgrowth, severe developmental defects, and maternal d ... | 2014 | 25130206 |
| [resting metabolic rate, stress, testosterone, and induced immune response in "spring" and "fall" males of campbell dwarf hamsters. rearing under the long day conditions]. | we have studied morphological and physiological traits of even-young males of campbell dwarf hamsters (phodopus campbelli thomas, 1905) born at the end of summer ("fall males") and at the end of winter ("spring males") in a vivarium with constant 14-hour day length (14d:10n). after removal from parental cages at the age of one month, males were kept in isolation under the same light conditions. the results obained signify the statistical difference between "fall" and "spring" males in resting me ... | 2014 | 25438568 |
| [decorative forms of hamsters phodopus (mammalia, cricetinae): an analysis of genetic lines distribution and peculiarities of hair changes]. | three species of dwarf hamsters (genus phodopus, family cricetidae) inhabit some regions of russia, kazakhstan, mongolia, and china, each having quite extensive range. in recent decades, the dwarf hamsters became widely spread all over the world, initially as laboratory animals and later as popular pets. by now, there is lot of decorative breed lines and colored forms of these animals. comparison of mtdna nucleotide sequences of dwarf hamsters acquired in pet shops of some countries in europe, s ... | 2012 | 22590908 |
| [nursing father--myth or reality? the role of secretions of father-male specific skin glands in survival and of campbell's hamsters offspring (phodopus campbelli thomas, 1905; cricetidae, rodentia)]. | biparental campbell's hamster (phodopus campbelli) were used for testing the hypothesis that secretions of father-male specific skin glands (midventral gland and additional sacculi) may promote juveniles survival in mother's absence. for the hypothesis testing, juveniles at age 7 or 8 days were left either with father or with mother till day 30, and their survival and growth rate were compared. amongst males, there were 26 surgically operated specimens (with midventral gland and sacculi removed, ... | 2010 | 20583632 |
| operant behavior in dwarf hamsters (phodopus campbelli): effects of rate of reinforcement and reinforcer flavor variety. | we investigated operant behavior in a novel species, the dwarf hamster (phodopus campbelli). in two experiments, hamsters were trained to lever-press for food reinforcement. in experiment 1, rate of reinforcement was manipulated across conditions using four variable-interval schedules of reinforcement (delivering one to eight reinforcers per min). as predicted, within-session decreases in responding were steepest on the richest schedule. in experiment 2, lever-pressing was reinforced by either a ... | 2010 | 20188801 |
| social cues influence foraging in dwarf hamsters (phodopus campbelli). | in 2 experiments, dwarf hamsters (phodopus campbelli) were trained to find palatable foods in an open field. the location of each food patch remained the same throughout each experiment, and only 1 food was available per day. once subjects had been trained to find each food in its unique location, they progressed to a testing phase in which subjects' mates were allowed to eat and hoard the food that was available in the open field each day. the foods that subjects' mates brought back to the home ... | 2009 | 19450030 |
| intraspecific organization of dwarf hamsters phodopus campbelli and phodopus sungorus (rodentia: cricetinae) basing on mtdna analysis. | | 2017 | 19341080 |
| comparison of the activity of some phosphatases in the midventral gland and nonspecific sebaceous glands of the neck in the campbell hamster (phodopus campbelli). | | 2017 | 19213433 |
| aromatase inhibition during adolescence reduces adult sexual and paternal behavior in the biparental dwarf hamster phodopus campbelli. | previous studies have failed to identify an activational role for estradiol in the paternal behavior of phodopus campbelli fathers. however, none of these studies addressed a developmental role that estradiol might play in establishing paternal behavior in this species. males were orally administered the aromatase inhibitor letrozole (1 mg/kg/day) for three days at 18, 34, or 90 days of age. as adults, males were tested for paternal and sexual behavior. letrozole treatment at 18 days resulted in ... | 2008 | 18762188 |
| in uniparental phodopus sungorus, new mothers, and fathers present during the birth of their offspring, are the only hamsters that readily consume fresh placenta. | placentophagia is common among parturient female mammals but non-parturient females generally refuse placenta. biparental male dwarf hamsters (phodopus campbelli) readily consume placenta. the present study quantified placentophagia and liver acceptance in the closely related siberian hamster p. sungorus in which males do not participate in the birth and are not responsive to a displaced pup. sexually naïve p. sungorus males and females refused both placenta and liver (all groups <10%). reproduc ... | 2006 | 17016837 |
| individual variation in cortisol responses to acute "on-back" restraint in an outbred hamster. | an outbred species of dwarf hamster (phodopus campbelli) was used to assess between-individual variability in the response to, and recovery from, a one-time stressor of 6 min of physical restraint in a subordinate, on-back, position. four repeated plasma samples were drawn under home-cage isoflurane anesthesia from 33 males and 38 females 50 min before, and then 10, 60, and 120 min after the stress onset. plasma cortisol concentrations were higher in females than males, but there was no evidence ... | 2006 | 16697381 |
| paternal responsiveness in biparental dwarf hamsters (phodopus campbelli) does not require estradiol. | males of the biparental hamster species phodopus campbelli act as midwives and are responsive to an experimentally displaced pup. males also have peripheral estradiol concentrations that are similar to conspecific females. castration reduces peripheral estradiol, yet does not affect paternal responsiveness despite the known role of estradiol in maternal behavior. synthesis of estradiol within the central nervous system, however, might not be affected by castration. males received implants of osm ... | 2006 | 16458311 |
| placentophagia in naïve adults, new fathers, and new mothers in the biparental dwarf hamster, phodopus campbelli. | placentophagia in mammals typically occurs only in females during the birth. male hamsters, phodopus campbelli, with an extensive paternal behavior repertoire eat placenta during the birth and as alloparental juveniles. two fresh placentae were presented to sexually naïve males and females covering the developmental range from puberty through reproductive maturity and into senescence. expectant parents and new mothers were also tested. placentophagia occurred in both sexes at all developmental s ... | 2005 | 16136563 |
| comparative investigation of the volatile urinary profiles in different phodopus hamster species. | stir bar sorptive extraction method was used for investigation of the urinary volatile profiles in male and female phodopus campbelli and phodopus sungorus hamsters. additionally, female phodopus roborowsky urinary profiles were characterized. a quantitative analytical approach allowed comparisons of 17 selected compounds in urine. results showed that campbelli and sungorus species show similar urinary volatile profiles for males and females. differences appeared only in concentrations. several ... | 2005 | 16124237 |
| castration reduces male testosterone, estradiol, and territorial aggression, but not paternal behavior in biparental dwarf hamsters (phodopus campbelli). | biparental male hamsters, phodopus campbelli, act as midwives during the birth of their litter and are highly responsive to an experimentally displaced pup. they also have high peripheral concentrations of estradiol, a hormone with known roles in maternal behavior. surgical castration during the gestation of their first litter was used to investigate the source of that estradiol and the functional role of testicular sex steroids in paternal responsiveness. in experiment i, castration reduced bot ... | 2005 | 15925370 |
| male and female prolactin receptor mrna expression in the brain of a biparental and a uniparental hamster, phodopus, before and after the birth of a litter. | prolactin receptor (prl-r) mrna transcript level was quantified in the choroid plexus (chp) of a naturally biparental hamster, phodopus campbelli, and its otherwise similar, yet nonpaternal, sibling species, phodopus sungorus. pair-housed males and females on the day before the birth of their first litter (g17), the day after birth (l1), lactation day 5 (l5), and unpaired animals that were sexually naïve, were tested. prl-r mrna transcript level relative to total rna, was evaluated by reverse tr ... | 2005 | 15796758 |
| estradiol and progesterone in paternal and non-paternal hamsters (phodopus) becoming fathers: conflict with hypothesized roles. | phodopus campbelli has an extensive paternal behavior repertoire whereas the closely-related phodopus sungorus is not paternally responsive to a displaced pup. for the first time in a naturally paternal mammal, male estradiol and progesterone were determined during two critical phases: (1) the transition from sexually naive male to paired, expectant father that occurs in the absence of stimuli from pups (sexually naive males, paired males on g8, g12, g15, or g17 of the 18-day gestation) and (2) ... | 2005 | 15777806 |
| ontogeny of the transition from killer to caregiver in dwarf hamsters (phodopus campbelli) with biparental care. | biparental phodopus campbelli and uniparental p. sungorus juvenile litters (2 males, 2 females) both consumed amniotic fluid and placenta during the birth of younger siblings. three days later, p. campbelli juveniles were most responsive to a displaced younger sibling. thus, p. campbelli are responsive to pups as juvenile alloparents and as new parents; however, at intervening ages, infanticidal attack (bite) was seen. at 5, 7, 9, 11, or 13 weeks of age, male and female p. campbelli were given a ... | 2005 | 15732058 |
| dopamine agonist treatment before and after the birth reduces prolactin concentration but does not impair paternal responsiveness in djungarian hamsters, phodopus campbelli. | male djungarian hamsters, phodopus campbelli, are highly parental and experience a late-afternoon prolactin surge before the birth that is not seen in a closely related species, p. sungorus, which lacks paternal care. at the same stage, female prolactin is needed for later maternal behavior. male prolactin was suppressed in first-time fathers before the birth of the litter using two different dopamine agonists, bromocriptine mesylate and cabergoline. plasma prolactin concentration confirmed the ... | 2005 | 15708766 |
| the role of symbiotic bacteria living in specific complexes in mouth corners in the regulation of the normal vital activity of the dwarfhamster phodopus campbelli. | | 2017 | 15587797 |
| neonatal anesthesia for studies of hamster parental behavior when infanticidal aggression is a possibility. | experiments involving investigation of the neuroendocrine basis for paternal care in rodents risk activation of aggressive behavior toward pups. to minimize pain and suffering during tests of parental responsiveness requiring retrieval of a displaced pup to its nest, a method of anesthetizing the pup was developed in djungarian hamsters, phodopus campbelli. a surgical plane of anesthesia, as measured by criteria, such as respiratory depression, loss of the pedal reflex, and failure to increase r ... | 2004 | 15134367 |
| paternal hamsters mechanically assist the delivery, consume amniotic fluid and placenta, remove fetal membranes, and provide parental care during the birth process. | we report the first description of a male mammal behaviorally participating in the birth of his young. djungarian hamsters, phodopus campbelli, are naturally biparental and males contribute to pup survival and growth through direct paternal care and indirect effects on maternal physiology. males of the closely related siberian hamster, p. sungorus, have only seasonal opportunities to interact with pups and neither contribute to pup survival and growth nor provide extensive paternal care under la ... | 2000 | 10753581 |
| fathers, fat, and maternal energetics in a biparental hamster: paternal presence determines the outcome of a current reproductive effort and adipose tissue limits subsequent reproductive effort. | djungarian hamster females, phodopus campbelli, are severely constrained in their ability to reproduce successfully and lose 20% of their body weight by the time pups are weaned. in the wild and in the laboratory, biparental care improves maternal reproductive success. two experiments quantified the effects of paternal presence and partial lipectomy [surgical depletion of parametrial white adipose tissue (pwat) on day 8 of the 18-day gestation] on maternal energy balance, reproductive success, a ... | 2000 | 10860683 |
| [characteristics of the first meiotic division in hamster hybrids obtained by backcrossing phodopus sungorus and phodopus campbelli]. | spermatocytes of fertile, subfertile, and sterile hamster hybrids obtained by backcrossing phodopus sungorus and ph. campbelli were analyzed under light and electron microscopes. light microscopy showed that early meiosis was blocked in pachitene in the spermatocytes of sterile hybrids. the x and y chromosomes were dissociated in metaphase i in several fertile and subfertile animals. electron microscopic analysis of the synaptonemal complex (sc) revealed a disturbed synapsis of sex chromosomes a ... | 1999 | 10495939 |
| [the attraction of campbell (phodopus campbelli) and djungarian (phodopus sungorus) hamster pups to the odor of the secretion from specific complexes in the corners of the mouth of the mother]. | the hamsters, phodopus campbelli and ph. sungorus have additional sacculi at the opening of the cheek pouches. the secretion of additional sacculi is very important for normalization of some aspects of the hamsters' physiology, as well as growth and development of pups, and also for chemical communication. we studied the role of the mother's additional sacculi secretion in mother-youngs interaction. it was shown that this secretion is most attractive for pups of both species from 6th to 11th day ... | 2016 | 10423934 |
| microphthalmia: a morphogenetic lethal mutation of the campbelli hamster (phodopus campbelli). | microphthalmia is a new mutation of the campbelli hamster (phodopus campbelli) that is controlled by an incomplete dominant autosomal gene mi. the dorsal coat of the heterozygote had dark markings on a white background. the dark markings appear on the head, back, and rump. their color is very similar to that of the wild type, but slightly lighter. the pupil and iris of the heterozygote are black with reddish tinge. the homozygote has pure white fur all over the body and shows a smaller body size ... | 2006 | 9487680 |
| paternal care reduces maternal hyperthermia in djungarian hamsters (phodopus campbelli). | throughout lactation, maternal body temperature, nest attendance, activity level and reproductive success of solitary female djungarian hamsters housed at the recommended ambient temperature of 23 degrees c (canadian council on animal care guidelines) were compared with those of paired females housed at the same temperature and with solitary females housed at the natural burrow temperature of 18 degrees c. as expected, cooler ambient temperature improved pup survival and weaning weight. likewise ... | 1997 | 9402613 |
| nature's knockout: the mel1b receptor is not necessary for reproductive and circadian responses to melatonin in siberian hamsters. | the pineal hormone melatonin regulates seasonal reproduction and influences the timing of circadian rhythms. the mel1a and mel1b receptors are the high-affinity melatonin receptors present in mammals. unexpectedly, the mel1b receptor gene of the siberian hamster, phodopus sungorus, cannot encode a functional receptor; two nonsense mutations are present within the coding region. southern blot analysis indicates that this is a single copy gene. the mel1b receptor gene is nonfunctional in outbred p ... | 1996 | 8923472 |
| [heterospecific social factors influencing the rate of sexual maturation of campbell's hamsters (phodopus campbelli thomas, 1905): the role of cross-rearing and secretion of the midventral gland of male djungarian hamsters (phodopus sungorus pallas, 1773)]. | | 1996 | 8998453 |
| [effect of secretions of specific cutaneous glands on enzymatic activity of a series of regions in the digestive tract in campbell hamsters (phodopus campbelli, thomas, 1905)]. | | 1996 | 8963220 |
| albino and pink-eyed dilution mutants in the russian dwarf hamster phodopus campbelli. | the coat color mutant genes albino (c) and pink eyed dilution (p) are described in the dwarf hamster species phodopus campbelli. both genes are inherited as redessive to normal. tests for linkage between the two genes gave negative results. the apparent absence of linkage is contrasted with linkage between homologous alleles c and p in other species of rodents. | 2005 | 8830094 |
| odors providing sexual information in djungarian hamsters: evidence for an across-odor code. | experiments were conducted to determine the repertoire of odors that are involved in sexual recognition and communication about reproductive state in djungarian hamsters (phodopus campbelli). by examining the preferences of males for odors of females over those of males, it was found that some odors support preferences across female reproductive states, other odors induce preferences only during estrus, and yet other odors do not elicit sexual preferences. similarly, female preferences for male ... | 1996 | 8724176 |
| progesterone, estradiol, and prolactin involvement in lactation, including lactation following a postpartum mating, in the djungarian hamster (phodopus campbelli). | the endocrinology of lactation in the djungarian hamster was investigated through once-daily sampling of females on days 0, 3, 6, 9, 12, 15, and 18 postpartum. serum prolactin (prl) was elevated during early lactation but declined with time. serum progesterone (p4) levels were uniformly low, and serum estradiol (e2) levels increased after day 9. new cl were formed after the postpartum ovulation and persisted throughout lactation. during the first 9 days, the cl had the high p4 content typical of ... | 1995 | 7780008 |
| daily patterns of pituitary prolactin secretion and their role in regulating maternal serum progesterone concentrations across pregnancy in the djungarian hamster (phodopus campbelli). | profiles of serum prolactin (prl) and progesterone (p4) were determined in repeatedly (every 2 h) sampled female djungarian hamsters (phodopus campbelli) over a 24-h period on days 3, 6, 9, 12, and 15 of the 18-day pregnancy. the first half of pregnancy was characterized by significant surges of prl within a 2-h period around dawn (0500 h) and dusk (1900 h), with some females also showing a weak midday surge at 1300 h. by day 9, dusk and midday surges were absent, but the dawn surge remained at ... | 1995 | 7780003 |
| [removal of the midventral gland affects behavior and mass of the campbell hamster (phodopus campbelli thomas, 1905) adrenal glands: indications of the presence of a functional connection of specific cutaneous glands with the neuroendocrine system]. | | 1995 | 7711661 |
| ontogeny of thermoregulation in the djungarian hamster (phodopus campbelli). | at birth, altricial djungarian hamster pups require exogenous heat to grow and gain little benefit from huddling with their littermates. by day 6 huddled pups begin effective thermogenesis although isolated pups do not show spontaneous increases in temperature until day 9. on day 12, isolated pups can resist cooling for short periods of time and huddles do not cool within a 15 min test. by day 15, isolated pups can thermoregulate, although at a lower core body temperature than is typical of adul ... | 1995 | 7878103 |
| photoperiodic differences during development in the dwarf hamsters phodopus sungorus and phodopus campbelli. | the dwarf hamsters phodopus sungorus and to a lesser extent phodopus campbelli are widely used to study pineal physiology and seasonal reproduction because of their marked responses to photoperiod in adulthood. these species are frequently confused, partly because the common names "siberian hamster" and "djungarian hamster" are applied to both, often interchangeably. the current study examines whether the effects of photoperiod on reproductive maturation and prolactin secretion differ between th ... | 1994 | 7821784 |
| [the participation of vaginal bacteria in phodopus campbelli in the chemical communication between male and female]. | phodopus campbelli commonly occurs in dry steppe and semidesert zone of south siberia, mongolia and china. using radiotelemetry we found that a male has to cover about 2 km from his burrow to encounter a receptive female. female in estrus marks a small area around its burrow by vaginal smear. experiments were carried out in laboratory to discover the nature of this strong signal. in a "open field" area four boxes within stimuli we recorded the time complemented spent by males near boxes to study ... | 2016 | 7804100 |
| prolactin, follicle-stimulating hormone, and luteinizing hormone levels during preimplantation in the djungarian hamster (phodopus campbelli). | the reproductive physiology of female djungarian hamsters (phodopus campbelli) varies in several ways from that of more conventional laboratory models. in this study we investigated serum and pituitary levels of prolactin (prl), lh, and fsh during preimplantation pregnancy. data were collected from independent females every 2 h from 2200 h on proestrus through 0600 h on day 5. prl levels in serum showed a distinct, biphasic, nocturnal surge pattern. levels during the light phase were low, with v ... | 1994 | 8080920 |
| spontaneous termination of an induced pseudopregnancy in the djungarian hamster, phodopus campbelli. | the mechanisms which underlie the termination of a functional pseudopregnancy and the return to a behavioral estrus in the djungarian hamster, phodopus campbelli, were investigated through changes in (1) serum prolactin concentrations; (2) progesterone and estradiol concentrations in the serum and extracted corpus luteum, ovulatory follicle, and non-luteal portion of the ovary; and (3) corpus luteum and non-luteal ovary weight. females were asynchronous in the timing of resumption of behavioral ... | 1994 | 7927283 |
| endocrinology of the pregnant djungarian hamster phodopus campbelli. | factors regulating maternal serum progesterone concentrations during pregnancy in the djungarian hamster phodopus campbelli were investigated through changes in (1) concentrations of progesterone and oestradiol in the serum and extracted corpus luteum, non-luteal ovary, and placenta during late pregnancy, (2) prolactin concentrations in the serum, and (3) mass of the fetus, placenta, corpus luteum and non-luteal ovary. early pregnancy (days 1-4) was characterized by surges of prolactin, corpus l ... | 1994 | 8064666 |
| [communicative function of the secretion from supplemental sacs in the campbell hamster (phodopus campbelli thomas, 1905) and djungarian hamster (phodopus sungorus pallas, 1773) cheek pouch: role in individual recognition]. | | 1994 | 8186746 |
| [marking behavior of the female campbell hamster (phodopus campbelli thomas, 1905); correlation with the reproductive cycle phase and functional activity of the midventral gland]. | | 1994 | 8167603 |
| disruption of body temperature and behavior rhythms during reproduction in dwarf hamsters (phodopus). | the internal gestation and subsequent lactation of mammalian reproduction represent a considerable physiological challenge. the extent of disruption in the daily rhythm of four parameters, core body temperature, nest attendance, activity, and wheel running, was monitored in djungarian hamster (phodopus campbelli) and siberian hamster (p. sungorus) females implanted intraperitoneally with biotelemetric thermistors. the amplitude of each rhythm decreased during late gestation, culminating in a sub ... | 1994 | 8153179 |
| [regeneration of a specific midgut skin gland after its partial resection in the djungarian hamster (phodopus campbelli, rodentia, mammalia)]. | | 1993 | 8298490 |
| alteration of the bed nucleus of the stria terminalis (bnst) in young female djungarian hamsters (phodopus campbelli) exposed to adult males. | central components of the vomeronasal system appear to mediate extrahypothalamic control of gonadotropin release during male-induced acceleration of puberty onset in female rodents. in order to describe the bed nucleus of the stria terminalis (bnst) and to determine whether this component of the vomeronasal system is altered following early puberty onset, the anterior bnst of female djungarian hamsters (phodopus campbelli) was subdivided into three regions: medial, lateral, and ventral. the cros ... | 1993 | 8297321 |
| [the ontogeny of additional saccules in the orifice of the cheek pouches in hamsters (phodopus campbelli thomas, 1905 and phodopus sungorus pallas, 1773): a morphometric analysis]. | time changes in functional activity of the recently described additional sacs in the orifice of cheek pouches (as) has been studied in one-month-old and adult phodopus sungorus and p. campbelli. the most intense as growth and increase in their secretory activity falls on the second decade of the first month. it coincide with transition to their own feeding by coarse crust. although there is no sexual dimorphism in the as mass or the amount of their secret, time pattern of growth is different in ... | 2016 | 8260886 |
| induced components in the spontaneous ovulatory cycle of the djungarian hamster (phodopus campbelli). | although djungarian hamsters, phodopus campbelli, show regular, 4-day spontaneous estrous cycles when tested for behavioral receptivity, this study shows that over 50% of 624 virgin females paired with males show their first behavioral estrous on the third day after pairing. the observed pattern is compared against predictions of estrous synchrony and/or estrous cycle suppression models. they fail to explain the high incidence of mating on the third day, and are incompatible with our current und ... | 1993 | 8248389 |
| [behavior of the campbell hamster (phodopus campbelli thomas, 1905) in nature: confirmation of the biological signal field theory]. | | 1993 | 8260931 |
| preimplantation endocrinology in the djungarian hamster (phodopus campbelli): progesterone, estrogen, corpora lutea, and embryonic development. g. | this study reports the results of a detailed investigation of pregnancy in the djungarian hamster, phodopus campbelli, with a 2-h time resolution from 2000 h on proestrus (day 0) through 0600 h on day 5. comparisons of the serum levels of progesterone (p4) and estradiol-17 beta (e2), along with the extractable content of each in the corpora lutea and the nonluteal portion of the right ovary, were used to assess the sources and circulating levels of these steroids throughout preimplantation pregn ... | 1993 | 8218648 |
| [the effect of specific formations in mouth corners on physiologo-morphological parameters of the adult campbell hamster (phodopus campbelli, thomas, 1905)]. | | 1993 | 8358314 |
| social influences on reproductive development and fertility in female djungarian hamsters (phodopus campbelli). | social influences on the sexual maturation of female djungarian hamsters were investigated in two experiments. in the first experiment females were housed from weaning with an adult male, by themselves, or with a weanling sister. maturation was accelerated in females housed with males as indicated by younger age at first ovulation, increased rates of ovarian and uterine growth, and lower lh levels at some ages. maturation was delayed in females housed with sisters compared to those housed alone ... | 1992 | 1398551 |
| [cytogenetic results of hybridization of hamsters rhodopus sungorus and phodopus campbelli]. | | 1992 | 1486345 |
| [functional morphogenesis in organ cultures of the middle abdominal specific skin gland of the djungarian hamster (phodopus campbelli, rodentia, mammalia)]. | | 1992 | 1425182 |
| [additional sacculi in the orifice of the cheek pouches of campbell's hamster (phodopus campbelli thomas, 1905; cricetidae, rodentia)]. | | 1991 | 1855441 |
| differential effects of paternal presence on pup survival in two species of dwarf hamster (phodopus sungorus and phodopus campbelli). | the effect of the presence or absence of the male, and of decreased ambient temperature (21 degrees c vs. 4 degrees c) on litter survival, pup survival and pup growth was measured from birth through day 18 after birth in siberian (p. sungorus) and djungarian (p. campbelli) hamsters. siberian hamsters were not significantly affected by the experimental manipulations. in contrast, whereas 100% of litters and 95% of pups were successfully raised to weaning at 21 degrees c by paired djungarian hamst ... | 1989 | 2756037 |
| [secretion of midventral glands of male djungarian hamsters (phodopus campbelli thomas, 1905) contains a factor regulating sexual maturation of the offspring]. | | 1989 | 2612355 |
| male-female interactions across the female estrous cycle: a comparison of two species of dwarf hamster (phodopus campbelli and phodopus sungorus). | recent studies in our laboratory have suggested that monogamy may be the preferred mating system in the djungarian hamster (phodopus campbelli), whereas the available evidence for the closely related siberian hamster (p. sungorus) does not show the same pattern. here we examine the behavior of male-female dyads of both species interacting during 1-hr tests in large, familiar habitats containing defensible nest boxes, food, and water. levels of aggression within pairs were low, compared with thos ... | 1987 | 3691057 |
| influence of pre- and post-copulatory pair contact on pregnancy success in djungarian hamsters, phodopus campbelli. | females housed with their mates for 3 or 4 days before mating took place (i.e. early in the oestrous cycle at the time of introduction to the mate) were significantly more likely to litter than were females housed with their mates for only 1 or 2 days before mating. the duration of post-copulatory pair contact had a complex effect on pregnancy success. while only 41% of females littered when they had 24 h of post-copulatory pair contact, females exposed to either longer or shorter durations of p ... | 1987 | 3598960 |
| estradiol and estrogen receptor α in the mpoa and mea in dwarf hamster (phodopus campbelli) fathers. | e2 and its alpha receptor (erα) have an essential role in the regulation of maternal behavior. in dwarf hamster (phodopus campbelli), e2 facilitates the display of paternal care, and it is possible that erα is part of the neuroendocrine mechanisms that regulate this behavior. the aim of this study was to analyze the influence of copulation, cohabitation with the pregnant mate and the presence of the pups on paternal behavior, circulating e2 levels and the presence of erα in the medial preoptic a ... | 2020 | 31816282 |
| females choose gentle, but not healthy or macho males in campbell dwarf hamsters (phodopus campbelli thomas 1905). | androgen-dependent male sexual traits (sts) as well as immunocompetence are theoretically assumed to be key indicators of a male's quality for the mate-choosing female. we studied mate choice by sexually motivated (sm) females of campbell's dwarf hamsters. females chose between 2 tethered male siblings that differed in expression of sts. males were unrelated to the female and able to contact and copulate with her. in both males, we measured sex-related morphology of body mass, mid-ventral specif ... | 2017 | 29492014 |
| an increase in estradiol facilitates the onset of paternal behavior in the dwarf hamster (phodopus campbelli). | in the dwarf hamster (phodopus campbelli), activational effects of testosterone (t) and estradiol (e2) in the regulation of paternal behavior have been repeatedly rejected because peripheral concentrations of e2 do not change across the reproductive cycle of males. further, castration no affected paternal behavior despite that both t and e2 concentrations decreased significantly. however, the role of these hormones has not been evaluated in models of castration and hormonal replacement in virgin ... | 2018 | 29425672 |
| [female mate choice, male-male competition, and male sexual traits: experimental study of sexual selection directedness in campbell's dwarf hamster (phodopus campbelli thomas 1905)] | we studied the relationship between female mate choice and male-male competition in campbell's dwarf hamster. sexually motivated (sm) females chose between two tethered male siblings that differed in expression of sexual traits. males were unrelated to the female and able to contact and copulate with her. the same males were used in encounter experiment with the following free access of competing male to another sm female. we measured males' sex-related morphology of body mass, mid-ventral speci ... | 2018 | 30024675 |
| the roborovski dwarf hamster is a highly susceptible model for a rapid and fatal course of sars-cov-2 infection. | the coronavirus disease 2019 (covid-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (sars-cov-2) has precipitated an unprecedented and yet-unresolved health crisis worldwide. different mammals are susceptible to sars-cov-2; however, few species examined so far develop robust clinical disease that mirrors severe human cases or allows testing of vaccines and drugs under conditions of severe disease. here, we compare the susceptibilities of three dwarf hamster species (phodop ... | 2020 | 33271063 |