Inhibition of ovarian function in subordinate female marmoset monkeys (Callithrix jacchus jacchus).

Plasma concentrations of progesterone, cortisol, LH and prolactin were measured in dominant and subordinate female marmosets in 10 well-established peer groups. Subordinate females never ovulated, had a reduced LH response to LH-RH and showed no positive feedback LH surge after oestrogen administration. There was no evidence of elevated plasma cortisol levels or hyperprolactinaemia in subordinates and all showed a similar prolactin response to TRH in comparison with dominants. However, subordinates showed a reduced prolactin response to metoclopramide. These results clearly indicate that high circulating levels of cortisol or prolactin are not responsible for the inhibition of ovulation in female marmosets.