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PubMed2000

Adrenocortical function in a new world primate, the marmoset monkey, Callithrix jacchus.

The function of the adrenal cortex of the marmoset monkey Callithrix jacchus has been investigated. In common with other New World primates, these animals seem to be glucocorticoid resistant. Blood and adrenal glands were obtained from male and female animals under terminal pentobarbitone anesthesia. Dispersed adrenal cell preparations were obtained by treatment with collagenase and incubated with ACTH(1-24), (0.1-1000 nM) angiotensin II (0.1-1000 nM), dibutyryl cyclic AMP (dbcAMP; 30-1000 microM), and forskolin (FSK; 1-30 microM). Plasma cortisol levels (2113 +/- 449 ng/ml male; 3858 +/- 429 ng/ml female) were found to be 10- to 20-fold higher than those quoted for Old World primates and man. The cell preparations showed no significant response to any dose of ACTH tested (0.1-1000 nM), although addition of exogenous precursor (22R-hydroxycholesterol, 2.5 microM) resulted in an increased yield of cortisol and aldosterone. Cyclic AMP production was increased in response to forskolin (1-30 microM) but not ACTH(1-24) (1-1000 nM). In addition, dose-related responses to angiotensin II (maximal stimulation of 316 +/- 49% basal aldosterone at 100 nM angiotensin II), dbcAMP (maximal stimulation of 449 +/- 24% basal cortisol at 300 microM dbcAMP), and forskolin (maximal stimulation of 394 +/- 31% basal cortisol at 10 microM FSK) were obtained. The lack of a response in vitro to ACTH in C. jacchus cannot, therefore, be attributed either to general failure of the cells or to defects in postreceptor signaling mechanisms. The results suggest that there is a reduction in adrenal ACTH receptor number or affinity, with a high basal production rate in vivo maintaining the elevated plasma cortisol levels.

Adrenal Cortex↗
PubMed1997

Social and developmental influences on reproductive function in female Wied's black tufted-ear marmosets (Callithrix kuhli).

Although marmoset social groups may contain multiple adult females, reproduction is typically limited to one breeding female. A variety of endocrine and behavioral mechanisms have been identified that regulate fertility among female marmosets. In the present study, we assessed the mechanism(s) by which fertility is regulated in female black tufted-ear marmosets, Callithrix kuhli. The reproductive status of 10 daughters aged 2-24 months was evaluated by measuring concentrations of urinary pregnane-diol 3 alpha glucuronide (PdG) and luteinizing hormone (LH). Concentrations of the two hormones were typically low in daughters less than 12 months of age, and the profiles suggested anovulation (mean PdG < 2 micrograms/mg Cr and mean LH < 6 ng/mg Cr). Concentrations of PdG rose dramatically in females older than 12 months. Eight subadult daughters commenced ovulatory function while still living with their family, and the remaining two failed to ovulate. The onset of ovarian function coincided with a change in the social environment in two females, but the remaining six females commenced spontaneous ovarian activity that was not associated with any social or environmental factor (mean age: 15.6 +/- 1.6 months). Ovulatory function was monitored in five daughters while housed in their natal family group, while removed from the natal family group and housed singly, and while paired with an unrelated and unfamiliar male. The ovarian cycles of these females housed in the natal group were characterized by significantly shorter luteal phases and reduced PdG concentrations, relative to when the females were housed on their own, and relative to adult breeding females (n = 6). Stimulatory cues from unfamiliar males were not necessary to trigger regular ovarian function in females. In this species, the regulation of fertility in daughters is a complex combination of behavioral and endocrine factors.

Animals↗
PubMed1998

Close proximity of the heterosexual partner reduces the physiological and behavioral consequences of novel-cage housing in black tufted-ear marmosets (Callithrix kuhli).

The present studies assessed the extent to which heterosexual pairmates could buffer marmosets (Wied's black tufted-ear marmoset, Callithrix kuhli) against stress. Six male and six female marmosets from established groups were exposed to two experimental manipulations together with a control condition. Each condition lasted a total of 4 days. For the two experimental conditions, animals were removed from the family group and housed in a novel cage for 48 h in either the presence or the absence of the heterosexual pairmate. During the 48-h novel-cage housing period and for 48 h upon reunion of the subjects with the family group, concentrations of urinary cortisol were measured in the first void sample of the day and behavioral observations were conducted. When animals were housed alone in a novel cage they exhibited significant elevations in levels of urinary cortisol after 24 and 48 h of novel-cage exposure. In contrast, when marmosets were housed in the novel cage in the presence of the pairmate, levels of urinary cortisol did not change across the 4-day period. The presence of the social partner also reduced the behavioral manifestations of exposure to novelty. Upon reunion with the family group, animals that had been housed in the novel cage alone spent significantly more time in close proximity to the pairmate than animals that had been housed with the partner. A second experiment was conducted to determine the effect that separation from the pairmate, only (independent of any effects of novelty), had on levels of cortisol. Concentrations of urinary cortisol were measured in subjects housed in the familiar home cage, but in the absence of the pairmate, over a 48-h period and compared to concentrations of excreted cortisol immediately prior to separation. Separation from the pairmate did not elevate cortisol levels when the subject was housed in the home cage, suggesting that elevated cortisol levels in animals housed alone in the novel cage were in response to novelty exposure rather than to separation from the pairmate. Since the physical presence of the heterosexual partner reduced the physiological and behavioral effects of novel-cage housing, social attachments might function as homeostatic regulators of HPA function in marmosets.

Animals↗
PubMed2000

Pre- and postpartum sex steroids in female marmosets (Callithrix kuhlii): is there a link with infant survivorship and maternal behavior?

Recent studies in primates have suggested that pre- and peripartum sex steroid hormones may be important determinants of maternal behavior and motivation, since higher levels of prepartum estrogen are associated with maternal competency and infant survivorship. To test the cross-species generality of this finding, we monitored excreted profiles of estradiol (E(2)), progesterone metabolites (pregnanediol glucuronide; PdG), and E(2):PdG ratios throughout pregnancy in black tufted-ear marmosets (Callithrix kuhlii). Additionally, we wanted to determine the extent to which variability in maternal carrying effort was related to hormonal factors and relative levels of maternal experience. For six females, hormonal profiles were determined by enzyme immunoassay for two pregnancies, one in which infants survived at least 2 weeks postpartum and one in which infants did not survive. Our within-subjects analyses revealed significant differences in mean prepartum E(2) levels for females in the different infant survival conditions. In contrast to previous findings, however, females exhibited significantly higher prepartum E(2) levels when their infants did not survive a minimum of 2 weeks postpartum, relative to when their infants did survive. Maternal carrying effort was also negatively and significantly correlated with prepartum E(2) levels. Unlike previous reports in callitrichid primates, then, our data suggest that high concentrations of prepartum E(2) in callitrichid primates are not necessarily associated with competent maternal behavior and may instead be associated with poor infant survivorship and inadequate maternal care. Further, our results appear to be convergent with research focusing on human mothers and may represent a common underlying mechanism linking prepartum estrogen and postpartum affect and behavior in some primates.

Animals↗
PubMed2001

Interactions among paternal behavior, steroid hormones, and parental experience in male marmosets (Callithrix kuhlii).

Male black tufted-ear marmosets (Callithrix kuhlii) contribute to the rearing of their offspring. Here we evaluated predictions of hypotheses suggesting that (1) T and E2 influence infant-care behavior in male marmosets, (2) levels of T and E2 are modulated by paternal experience, and (3) paternal behavior and levels of T and E2 in male marmosets covary with stress. We observed the behavior of marmosets in their family groups following the birth of infants and evaluated urinary concentrations of T, E2, and the stress hormone cortisol (CORT) among fathers before and after the birth of young. Urinary levels of T, E2, and CORT were lower among males who carried infants at high rates than males who carried at low rates, and T and CORT levels were negatively correlated with carrying rates across all males. Males had significantly lower T levels while carrying the second compared to the first litter and slightly lower rates of infant-carrying, possibly due to assistance provided by offspring of the first litter. There were increases in CORT levels of fathers after the birth of the first litter, but decreases in CORT after the birth of the second. Our results suggest a relationship in C. kuhlii between paternal behavior, hormones, and paternal experience. Rates of infant-carrying appear to be linked to hormone levels, and hormone levels in turn are affected by experience caring for young. Our data also suggest that T, E2, and CORT have synergistic influences on infant-carrying behavior or alternatively that associations between T and E2 and rates of infant-carrying are influenced by stress or other glucocorticoid-related variables. Finally, we propose a hypothesis suggesting that experience-related changes in hormones reinforce the commitment of males to successful breeding partnerships.

Animals↗
PubMed2001

Bromocriptine administration lowers serum prolactin and disrupts parental responsiveness in common marmosets (Callithrix j. jacchus).

The influence of prolactin on parental responsiveness was investigated in eight unpaired, parentally inexperienced common marmosets (Callithrix jacchus; 6 female, 2 male). The marmosets were prescreened with infants (1-10 days of age) and required to exhibit short latency retrieval and infant carrying in at least three consecutive pretests as criterion for inclusion in this study. The marmosets were then administered the dopamine agonist bromocriptine (0.5 mg/0.5ml vehicle subcutaneously) and the vehicle alone (0.5 ml 10% ethanol solution) twice daily for 3 consecutive days in random order. Bromocriptine treatment reduced circulating prolactin to nondetectable levels. Bromocriptine treatment eliminated infant retrieval in four of the eight marmosets and was associated with significantly increased retrieval latencies and significantly reduced carrying durations in the four monkeys that continued to retrieve following bromocriptine treatment. When given the vehicle alone, the marmosets retrieved infants significantly faster than during pretests, suggesting a handling effect of the injection series. Bromocriptine treatments were associated with significantly increased movement during the tests. The results of this study indicate that prolactin and/or its regulatory neurotransmitters are involved in the control of the spontaneous display of parental responsiveness in common marmosets.

Aging↗
PubMed2002

Parent-daughter relationships and social controls on fertility in female common marmosets, Callithrix jacchus.

This study examined the reproductive status of mothers and daughters to determine if parent-eldest daughter interactions would influence the daughter's fertility in the cooperatively breeding common marmoset, Callithrix jacchus. Twice weekly fecal samples were collected for hormonal analyses from seven daughters and their mothers and analyzed for cortisol, estradiol, and progesterone by EIA. Behavioral data were collected three times weekly while the daughters were under three conditions: natal family, after removing from the family and paring with a novel male, and after removing from the paired condition and placed back with the family (renatal). Under the natal condition, five of the seven daughters exhibited ovarian cycles while their mother was pregnant or displaying ovarian cycling. The five cycling daughters spent significantly more time initiating affilative behaviors with their mothers than with their fathers and showed significant changes in their behavior over the length of the ovarian cycle. However, aggression, submission, and sexual behaviors were very low for daughters in the natal phase. No differences between cortisol levels were found for a daughter and her mother. Cortisol levels showed a significant and sustained increase upon pairing within the first 20 days. All females but one cycled while paired. Six of the seven females were accepted back into the family after pairing and five of the seven females were ovulating. These results suggest that marmoset daughters are not necessarily reproductively suppressed while living with the family. Additionally, these data suggest that female marmosets that leave their family to explore mating opportunities with other groups may return to their family without reproductive or aggressive consequences.

Adrenal Glands↗
PubMed1995

Parcellation of the frontal cortex of the New World monkey Callithrix jacchus by eight neurotransmitter-binding sites.

The most extensive development during primate brain evolution involves the cortex of the frontal lobe, especially its prefrontal region. The distribution of neurotransmitter receptors is unknown in this part of the cortex of New World monkeys. The respective distributions of eight different receptors for the transmitters L-glutamate (L-glu and NMDA), gamma-amino-butyric acid (GABAA), noradrenaline (alpha 1), acetylcholine (M1 and M2) and serotonin (5-HT1 and 5-HT2) were therefore studied in cortical areas of the frontal lobe of the lissencephalic New World monkey, Callithrix jacchus. The results are compared to earlier data on Old World monkeys in order to obtain insight into evolutionary trends at the level of chemical neuroanatomy. Our results indicate that the density and laminar pattern of some receptors change precisely at the cytoarchitectonic boundaries between different cortical areas, while some other receptors do not exhibit measurable changes. For example, the premotor area 6 can be distinguished from prefrontal areas by its high concentration of adrenergic alpha 1 receptors as labelled with [3H] prazosin, with only the cingulate area 24 showing higher values. In other cases, the receptor distribution changes within a cytoarchitectonically homogeneous area. Thus, area 8 can be subdivided into dorsal and ventral regions on the basis of the distribution of GABAA, muscarinic and serotonin receptors. Comparison of these results in a New World monkey with receptor distributions in other primate species reveals much larger interspecies differences in the areas of the frontal lobe than e.g. in the primary visual cortex.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

An ultrastructural study of early chorionic villus formation in the marmoset monkey (Callithrix jacchus).

The ultrastructural morphology of developing chorionic villi in the marmoset monkey (Callithrix jacchus) placenta was studied in pregnant monkeys at known time intervals after ovulation. In samples obtained at 45 days after ovulation the mesoderm, which consists of primitive foetal blood vessels, is seen to extend down into cytotrophoblast columns. Syncytiotrophoblast completely surrounds maternal blood vessels and both basal laminae and endothelial cells of maternal origin show signs of disorganisation and degradation. Syncytiotrophoblast is first observed to breach the maternal circulation in samples collected from animals at 60 days after ovulation; this results in discrete haemochorial villi randomly distributed throughout the placental bed. Samples obtained at 80 days after ovulation and term placental samples (145 days after ovulation) exhibit tertiary haemochorial villi throughout the placenta, similar to those seen randomly distributed at 60 days after ovulation.

Animals↗
PubMed1990

The topology of the thalamo-cortical projections in the marmoset monkey (Callithrix jacchus).

This paper addresses the question of a general topological principle of thalamo-cortical projections. In the lissencephalic primate brain of the common marmoset (Callithrix jacchus), large injections of horseradish peroxidase were made in various parts of the neocortex. These injections were placed in different animals and hemispheres along various caudo-rostral and medio-lateral gradients. Labelled cells in the thalamus were plotted and the labelling-zones resulting from several injections along a medio-lateral and two caudo-rostral cortical vectors were drawn into semi-schematic thalamic maps. These composite maps reveal a topological organization of the whole thalamo-cortical projection. The thalamic representation of the caudo-rostral and medio-lateral gradients indicate a rotation of the posterior relative to the anterior thalamus. An attempt is made to relate the organization of the thalamo-cortical projection to the development of the thalamus and the cortex. The cortex is divided into concentric zones around the sensory-motor and insular cortex. The thalamus is divided into corresponding projection zones. The topology of thalamo-cortical connections can then be regarded as a consequence of corresponding thalamic and cortical growth gradients. This is not only consistent with the general thalamo-cortical topology and the inversion of maps from thalamus to cortex, but also explains the continuity and overlap of thalamic projection zones in the pulvinar to widely separated cortical areas as the parietal, temporal and frontal association cortex.

Animals↗
PubMed1995

Localisation of the high affinity facilitative glucose transporter protein GLUT 1 in the placenta of human, marmoset monkey (Callithrix jacchus) and rat at different developmental stages.

In the present study, the facilitative D-glucose transporter protein GLUT 1 was localised by immunohistochemistry in the placenta of human, marmoset (Callithrix jacchus) and rat at different developmental stages. A polyclonal antiserum against a 13-amino-acid peptide of the GLUT 1 carboxy terminus was used. It identified a protein of around 50 kDa molecular weight in immunoblotting of the placental tissues. GLUT 1 was located in the syncytiotrophoblast, in cytotrophoblast cells and in fetal endothelium. Similar staining patterns, except in human extravillous cytotrophoblast cells, were observed at all differentiation stages, despite differences in the internal placental architecture of the species. In the marmoset placenta, GLUT 1 was undetectable in endothelial cells of maternal vessels. In rat placentae, trophoblastic giant cells, epithelial cells of both visceral and parietal yolk sac, yolk sac vessels and the stratum spongiosum were stained. Reichert's membrane did not immunoreact. Preadsorption of the antiserum with a 13-amino-acid peptide resulted in the loss of immunoreactivity. The results suggest that GLUT 1 is a prominent isoform of glucose transporters in mammalian placentae. It is generally abundant in placental cell populations bordering on the maternal and fetal circulations and may therefore facilitate an effective glucose supply to the fetus and placenta.

Animals↗
PubMed1987

The basement membrane of the persisting maternal blood vessels in the placenta of Callithrix jacchus.

Formation and morphology of the thickened basement membrane-like layer around the persisting maternal vessels of the Callithrix jacchus placenta were investigated from day 45 until term (day 142) using light, electron and immunofluorescence microscopy. Thickening occurs with the establishment of contacts between the vessels and the syncytiotrophoblast (day 48). Final thickness is reached at about day 100. The course of the vessels shows wide gaps where the maternal blood flows freely into the intertrabecular spaces. As revealed by electron microscopy, the extracellular sheath around the maternal vessels consists of an inner subendothelial basement membrane (3-6 microns) and an outer fibril-containing layer (2-4 microns). Cell debris is seen between the two layers and in the basement membrane. Plaques of granular and fine-filamentous material are incorporated into the fibril-containing layer. The synthesis of the basement membrane material is localized in the endothelial cells. Immunofluorescence microscopy reveals collagen types IV and V, laminin and heparan sulfate proteoglycan (BM-1) in the sheath around the persisting vessels. Fibronectin occurs only in certain areas or in the form of dots. Collagen types I and III are not seen in the region of the vascular wall. It can, therefore, be assumed that the subendothelial layer represents a genuine basement membrane; the fibrils consist of collagen type V and the plaques contain fibronectin. The existence of the thick perivascular sheath is attributed to the persistence and stability of the maternal vessels.

Animals↗
PubMed1987

The ultrastructure of early implantation in the marmoset monkey (Callithrix jacchus).

The ultrastructural morphology of the initial stages of implantation in the marmoset monkey (Callithrix jacchus) was studied in pregnant monkeys at known time intervals after ovulation. The earliest samples, obtained 13 days after ovulation, displayed both cytotrophoblast and syncytiotrophoblast. The cytotrophoblast was restricted to the blastocoel, whilst syncytiotrophoblast intruded to the endometrial basal lamina. At later stages, days 16 and 19 after ovulation, both cytotrophoblast and syncytiotrophoblast had extended laterally around the uterus, and the syncytiotrophoblast also extended deeper into the maternal tissues. The mesoderm layer was first discernible at 19 days after ovulation. At 23 days after ovulation the syncytiotrophoblast surrounded the maternal blood vessels entirely. In this study syncytiotrophoblast was not observed to breach the maternal blood vessels, even at 31 days after ovulation. Early cytotrophoblast columns could be seen at 31 days after ovulation. The endothelial cells lining the maternal blood vessels displayed hypertrophy from the earliest stages (day 13) onwards, although a true decidual response was only observed in samples of 23 and 31 days after ovulation.

Animals↗
PubMed1988

Embryotoxic effects of thalidomide-derivatives in the non-human primate Callithrix jacchus. I. Effects of 3-(1,3-dihydro-1-oxo-2H-isoindol-2-yl)-2,6-dioxopiperidine (EM12) on skeletal development.

The response of pregnant marmosets (Callithrix jacchus) to the thalidomide derivative EM 12 was evaluated. EM 12 was selected for these studies because it is more active than thalidomide and is much more stable for hydrolysis. Skeletal gross structural abnormalities were observed when EM 12 was given to marmosets for 3-7 days during the period between days 49 and 60 post ovulation. Using the treatment schedule finally adapted in our laboratory, i.e. treatment during days 51-57 post ovulation, doses of 5 (or 10) mg EM 12/kg body wt induced the typical limb abnormalities known from man with an 80-100% certainty. In some animals we could observe the typical pattern of abnormalities even with doses as low as 1 mg EM 12/kg body wt. Abnormalities of the skeleton induced during this sensitive period are described. None of these (except some bifurcations of ribs) were seen in any of the ten litters (23 fetuses) serving as controls during the period of the study.

Abnormalities, Drug-Induced↗
PubMed1988

Embryotoxic effects of thalidomide derivatives on the non-human primate Callithrix jacchus; 3. Teratogenic potency of the EM 12 enantiomers.

The teratogenic potencies of the enantiomers of 2-(2,6-dioxopiperidine-3-yl)-phthalimidine ( = EM 12), a teratogenic thalidomide analogue, were investigated in Callithrix jacchus, a primate very sensitive to the teratogenic action of this thalidomide analogue. The results indicate that the S-(-)-form of EM 12 is clearly more teratogenic than the R-(+)-form. The interpretation of the studies designed to evaluate stereo-selective differences in the teratogenicity of the enantiomers becomes difficult, since both enantiomers racemise in vivo with appreciable rates (Schmahl et al. 1988a, b). Therefore, it cannot be concluded as yet that the R-(+)-form lacks all teratogenic potential.

Abnormalities, Drug-Induced↗
PubMed1995

Recently amplified satellite DNA in Callithrix argentata (primates, Platyrrhini).

A satellite DNA has been cloned from the neotropical primate Callithrix argentata and designated CarB. The presence of the satellite was assayed in New and Old World primates by blot hybridization: CarB is highly amplified in the genomes of all three species belonging to the C. argentata species group (C. argentata, C. emiliae, C. humeralifer), but is either absent, or present in only minor amounts, in other primates, including the closely related species, C. jacchus. A completely sequenced CarB monomeric unit was 1528 bp in length and mapped to the telomeric C-band-positive regions of many C. argentata species group chromosomes. Sequence data from eight CarB clones indicated an average difference of 3.5% when base substitutions alone were counted. The hybridization and sequence data suggest that this satellite underwent a period of amplification and dispersal in the genome of a recent ancestor of the C. argentata species group.

Animals↗
PubMed1992

Studies on the developmental cycle of Trichospirura leptostoma (Nematoda: Thelaziidae). Experimental infection of the intermediate hosts Blatella germanica and Supella longipalpa and the definitive host Callithrix jacchus and development in the intermediate hosts.

The cockroaches Blatella germanica and Supella longipalpa can act as intermediate hosts of Trichospirura leptostoma as demonstrated by experimental infestation. The parasite developed from the embryonated egg into the infective larval stage (L3) in cockroaches within 5-6 weeks. After experimental infection of marmosets (Callithrix jacchus), eggs were first found in faecal samples (prepatency) at 8-9 weeks post-infection. Patency lasts about 2 years. Despite the presence of living adult worms in the marmosets' pancreas, no additional eggs were observed in their faeces after the patent period.

Animals↗