Cortisol response and ovarian hormones in juvenile and cycling female Cebus monkeys: effect of stress and dexamethasone

Abstract

We examined cortisol profiles in relation to ovarian hormones and their response to a repeated composite stressor with and without dexamethasone suppression. To evaluate the day-to-day changes in circulating cortisol relative to ovarian hormones, we subjected five adult female Cebus apella monkeys daily to restraint, sedation, transport to a neighboring room for femoral venipuncture, and return to the cage throughout the menstrual cycle. The cortisol response to the repeated stressor for blood collection, its relationship with the ovarian function, and the effects of dexamethasone were evaluated in six juveniles (18-24 months old) and five adult females in the luteal phase. Blood was sampled at time 0; then the monkeys received the vehicle and their blood was sampled again at 1, 2, 4, and 24 hr. This experiment was repeated 3 weeks later, with dexamethasone (i.m. 2 mg/Kg) injected instead of vehicle. Plasma aliquots were assayed for cortisol, progesterone, and estradiol. The results revealed that from middle infancy and throughout adulthood, hypercortisolism is the norm in female Cebus monkeys. The high cortisol values remained unchanged across the cycle despite the cyclic changes in estradiol and progesterone levels. Juvenile monkeys exhibited a higher cortisol response to stress than adults, and both juvenile and adult monkeys exhibited the typical suppression by dexamethasone. A rapid suppression of progesterone co-occurred in parallel with cortisol after dexamethasone injection in juvenile monkeys, suggesting that most circulating progesterone originates in the adrenals. In contrast, adult females exhibited an overincrement of progesterone levels, in parallel with a rise in cortisol, in response to the stressor, and this effect was exacerbated by dexamethasone. The findings suggest that hypercortisolism is insufficient to disrupt ovarian development toward a normal cyclical function, and that ovarian steroids have no influence on day-to-day circulating cortisol levels. On the other hand, the overincrement of progesterone levels induced by stress and/or glucocorticoids during the early luteal phase is unlikely to interfere with the development of this phase and implantation in this monkey species.

Variation of glucocorticoid metabolite levels is associated with survival demands in immature and reproductive demands in adult wild black capuchins (Sapajus nigritus)

“…Lynch, Ziegler, & Strier, 2002;Romero et al, 2009;Sapolsky, 1983;Setchell, Smith, Wickings, & Knapp, 2010;Strier, Ziegler, & Wittwer, 1999). We also investigated whether there is an increase in females' GCM levels caused by energy requirements related to the breeding season or to the late pregnancy (Bales, French, Hostetler, & Dietz, 2005;Bercovitch & Ziegler, 2002;Lahoz, Nagle, & Porta, 2007;Schoof, Jack, & Ziegler, 2014); and if reproduction-related factors can explain GCM variations better than food availability. Since immature individuals do not have reproduction-related requirements and deal with specific challenges associated to their development, as body growth (Altmann, 1998;Clymer, 2006), we expected that food availability would influence their GCM levels more than other events.…”

Análise endócrino-comportamental dos macacos-prego (cebus nigritus) que habitam o Parque Estadual Carlos Botelho

“…Em macacos Cebus do sexo feminino, um experimento recente mostrou que desde a metade da infância, e ao longo da idade adulta, o hipercortisolismo parece ser a norma (Lahoz et al, 2007). Lahoz e colaboradores observaram que fêmeas jovens apresentaram uma resposta maior de cortisol a estressores do que fêmeas adultas e que os altos valores de cortisol continuaram elevados durante o ciclo ovariano apesar de mudanças nas concentrações de estradiol e progesterona.…”

“…Esta correlação indicou que a maior parte da progesterona circulante era originária do mesmo local em que os GCs são produzidos, ou seja, das glândulas adrenais. Fêmeas adultas, por outro lado, apresentaram um aumento nos níveis de progesterona e cortisol em resposta a estressores, mas esse efeito foi exacerbado pela dexametasona (Lahoz et al, 2007).…”

“…Este resultado era esperado, uma vez que níveis maiores de progesterona são associados a fêmeas em ciclo ovariano (Lahoz et al, 2007).…”

“…Estas respostas apresentam uma interação complexa na qual o cortisol regula a liberação de hormônios gonadais, e estes aumentam, concomitantemente, a liberação de cortisol (Saltzman et al, 1998;Ziegler et al,1995). Além disso, parte dos hormônios sexuais é produzida pelas glândulas adrenais independentemente da função gonadal (Lahoz et al, 2007 A diminuição da disponibilidade de alimentos já foi associada a altos níveis de cortisol em babuínos (Sapolsky, 1986) e lêmures de calda anelada (Cavigelli, 1999).…”