Gonadotrophin‐Releasing Hormone (GnRH) Release in Marmosets I: <i>In Vivo</i> Measurement in Ovary‐Intact and Ovariectomised Females

Tannenbaum, P. L.; Schultz-Darken, Nancy; Saltzman, Wendy; Terasawa, Ei; Woller, Michael J.; Abbott, David H.

doi:10.1111/j.1365-2826.2007.01534.x

Cited by 12 publications

(8 citation statements)

References 67 publications

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“…Recent work even suggests that this could be a common feature of New World monkeys (Muller et al 2004), and according to recent concepts, the pituitary produces and releases chorionic gonadotropin instead of LH (Henke et al 2007). Studies on the relationship between GnRH release and induced chorionic gonadotropin release revealed a discordant pattern when compared with the GnRH and LH congruence described for rats and other primates (Tannenbaum et al 2007). These data imply some differences in the interplay between hypothalamus and pituitary in marmoset versus macaques and human.…”

Section: Ovarian Cycles In the Marmosetmentioning

confidence: 86%

Physiology and Endocrinology of the Ovarian Cycle in Macaques

Weinbauer

Niehoff²,

Niehaus³

et al. 2008

Toxicol Pathol

125

163

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Macaques provide excellent models for preclinical testing and safety assessment of female reproductive toxicants. Currently, cynomolgus monkeys are the predominant species for (reproductive) toxicity testing. Marmosets and rhesus monkeys are being used occasionally. The authors provide a brief review on physiology and endocrinology of the cynomolgus monkey ovarian cycle, practical guidance on assessment and monitoring of ovarian cyclicity, and new data on effects of social housing on ovarian cyclicity in toxicological studies. In macaques, cycle monitoring is achieved using daily vaginal smears for menstruation combined with cycle-timed frequent sampling for steroid and peptide hormone analysis. Owing to requirements of frequent and timed blood sampling, it is not recommended to incorporate these special evaluations into a general toxicity study design. Marmosets lack external signs of ovarian cyclicity, and cycle monitoring is done by regular determinations of progesterone. Cynomolgus and marmoset monkeys do not exhibit seasonal variations in ovarian activity, whereas such annual rhythm is pronounced in rhesus monkeys. Studies on pair- and group-housed cynomolgus monkeys revealed transient alterations in the duration and endocrinology of the ovarian cycle followed by return to normal cyclicity after approximately six months. This effect is avoided if the animals had contact with each other prior to mingling. These experiments also demonstrated that synchronization of ovarian cycles did not occur.

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Section: Ovarian Cycles In the Marmosetmentioning

confidence: 86%

Physiology and Endocrinology of the Ovarian Cycle in Macaques

Weinbauer

Niehoff²,

Niehaus³

et al. 2008

Toxicol Pathol

125

163

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“…Collectively, the work of a number of groups have highlighted the important role of CG in the regulation of reproductive function in New World primates [9, 10, 19, 24, 25]. The novel finding of pituitary expression of CG in New World primates raises a number of questions regarding its storage and secretion.…”

Section: Discussionmentioning

confidence: 99%

Tissue-specific expression of squirrel monkey chorionic gonadotropin

Vasauskas

Hubler

Boston

et al. 2011

General and Comparative Endocrinology

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Pituitary gonadotropins LH and FSH play central roles in reproductive function. In Old World primates, LH stimulates ovulation in females and testosterone production in males. Recent studies have found that squirrel monkeys and other New World primates lack expression of LH in the pituitary. Instead, chorionic gonadotropin (CG), which is normally only expressed in the placenta of Old World primates, is the active luteotropic pituitary hormone in these animals. The goal of this study was to investigate the tissue-specific regulation of squirrel monkey CG. We isolated the squirrel monkey CGβ gene and promoter from genomic DNA from squirrel monkey Blymphoblasts and compared the promoter sequence to that of the common marmoset, another New World primate, and human CGβ and LHβ. Using reporter gene assays, we found that a squirrel monkey CGβ promoter fragment (−1898/+9) is active in both mouse pituitary LβT2 and human placenta JEG3 cells, but not in rat adrenal PC12 cells. Furthermore, within this construct separate cis-elements are responsible for pituitary-and placenta-specific expression. Pituitary-specific expression is governed by Egr-1 binding sites in the proximal 250 bp of the promoter, whereas placenta-specific expression is controlled by AP-2 sites further upstream. Thus, selective expression of the squirrel monkey CGβ promoter in pituitary and placental cells is governed by distinct cis-elements that exhibit homology with human LHβ and marmoset CGβ promoters, respectively.

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“…Exposure to an unrelated adult male, by contrast, while playing a key role in the activation of sexual behaviour in females, does not influence the occurrence of ovulatory cycles . Moreover, ovulatory cycles in marmosets are not readily suppressed by such nonsocial challenges as surgery, illness or disruptive experimental procedures Schultz-Darken et al 2004;Tannenbaum et al 2007). Such precise and pronounced social regulation of gonadotrophin secretion and ovulatory function is not found in other anthropoid primates (with the exception of several other species of callitrichids (marmosets and tamarins); French 1997), but occurs in a number of other cooperative breeders (e.g.…”

Section: What Are the Physiological Mechanisms Underlying Reproductivmentioning

confidence: 99%

Reproductive skew in female common marmosets: what can proximate mechanisms tell us about ultimate causes?

2008

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Common marmosets are cooperatively breeding monkeys that exhibit high reproductive skew: most subordinate females fail to reproduce, while others attempt to breed but produce very few surviving infants. An extensive dataset on the mechanisms limiting reproduction in laboratory-housed and freeliving subordinate females provides unique insights into the causes of reproductive skew. Non-breeding adult females undergo suppression of ovulation and inhibition of sexual behaviour; however, they receive little or no aggression or mating interference by dominants and do not exhibit behavioural or physiological signs of stress. Breeding subordinate females receive comparable amounts of aggression to non-breeding females but are able to conceive, gestate and lactate normally. In groups containing two breeding females, however, both dominant and subordinate breeders kill one another's infants. These findings suggest that preconception reproductive suppression is not imposed on subordinate females by dominants, at a proximate level, but is instead self-imposed by most subordinates, consistent with restraint models of reproductive skew. In contrast to restraint models, however, this self-suppression probably evolved not in response to the threat of eviction by dominant females but in response to the threat of infanticide. Thus, reproductive skew in this species appears to be generated predominantly by subordinate self-restraint, in a proximate sense, but ultimately by dominant control over subordinates' reproductive attempts.

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Gonadotrophin‐Releasing Hormone (GnRH) Release in Marmosets I: In Vivo Measurement in Ovary‐Intact and Ovariectomised Females

Cited by 12 publications

References 67 publications

Physiology and Endocrinology of the Ovarian Cycle in Macaques

Physiology and Endocrinology of the Ovarian Cycle in Macaques

Tissue-specific expression of squirrel monkey chorionic gonadotropin

Reproductive skew in female common marmosets: what can proximate mechanisms tell us about ultimate causes?

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