The effects of a long‐term psychosocial stress on reproductive indicators in the baboon

Abstract

Psychosocial stress is thought to negatively impact fecundity, but human studies are confounded by variation in nutrition and lifestyle. Baboons offer a useful model to test the effect of prolonged mild stress on reproductive indicators in a controlled setting. Following relocation from social groups to solitary housing, a previously documented stressful event for non-human primates, daily urine samples, tumescence and menstrual bleeding were monitored in twenty baboons (Papio sp.) for 120–150 days. Specimens were assayed for estrone conjugates (E1C), pregnanediol-3-glucuronide (PDG), follicle-stimulating hormone (FSH), and cortisol. Linear mixed effects models examined 1) the effects of stress on frequency of anovulation, hormone levels, tumescence and cycle length, and 2) the relationship of cortisol with reproductive indicators. Despite cortisol levels indicative of stress, anovulation was negligible (1% in 102 cycles). PDG, FSH, cycle length, and tumescence declined during the first four cycles, but began recovery by the fifth. Cortisol was negatively associated with FSH but not associated with PDG, E1C or tumescence. Ovulation, E1C, and luteal phase length were not affected. Tumescence tracked changes in FSH and PDG, and thus may be a useful indicator of stress on the reproductive axis. Elevated cortisol was associated with reduced FSH, supporting a model of cortisol action at the hypothalamus rather than the gonad. After 4–5 menstrual cycles the reproductive indicators began recovery, suggesting adjustment to new housing conditions. In conclusion, individual housing is stressful for captive baboons, as reflected by cortisol and reproductive indicators, although ovulation, a relatively direct proxy for fecundity, is unaffected.

Exogenous adrenocorticotropic hormone affects genome‐wide DNA methylation and transcriptome of corpus luteum in sows

“…Studies from humans and animal models all indicate that in the reduction of the luteal phase, progesterone is the consistently observed hypothalamic-pituitary-gonadotropic response to stress (14,(35)(36)(37). In this study, the levels of progesterone were decreased by ACTH administration, which was consistent with results from other stress studies.…”

Perceived Stress, Reproductive Hormones, and Ovulatory Function

“…4 While both nonhuman primate and experimental studies in humans have helped inform mechanistic hypotheses, 5, 6 few studies have assessed the effects of stress on reproductive hormones and menstrual cycle function among premenopausal women; none of these prospectively assessed perceived stress or used more than one stress instrument. 7, 8 Global measures of psychosocial stress, such as the Perceived Stress Scale (PSS), 9 have been used for decades to study relationships between stress and adverse health outcomes.…”

The influence of quarantine on reproductive cycling in wild‐caught Baboons (Papio anubis)

“…For example, in a study assessing menstrual cycle length as a toxicological endpoint, new housing resulted in prolongation of cycle length for up to 5 months in 8 of 24 cynomolgus macaques [2]. Similarly, in a study of 18 baboons moved from social to single housing, cycle length was prolonged for 4-5 cycles post-move [8]. The association of prolonged quarantine with a greater percent time spent cycling observed here may indicate that environmental and social stability is associated with regularity of reproductive cycling.…”