Characteristics of the adrenal endocrine function of Papio hamadryas in the metopyrone test

Hormonal function of the adrenals of preadolescent and adult monkeys (Papio hamadryas) was examined by the metopyrone test. After a single injection of metopyrone the content of cortisol, 11-deoxycortisol, progesterone, pregnenolone, 17-hydroxyprogesterone and 17-hydroxypregnenolone was measured in the blood of monkeys by radioimmunoassay. The reasons for age-associated differences in the hormonal response of the primate adrenals to metopyrone injection are discussed. The conclusion is drawn on the advisability of a single metopyrone injection for studying functional reserves of the pituitary-adrenal system.     

Hormonal changes during the menstrual cycle of the baboon (Papio hamadryas)

Eleven unconjugated steroids were measured daily during a complete cycle in the peripheral plasma of six normally menstruating baboons (Papio hamadryas) by means of a radioimmunoassay procedure and the levels were compared with those found previously in 17 normally menstruating women. The patterns of progesterone and 20α-dihydroprogesterone were very similar to those found in women throughout the entire menstrual cycle. However, the ratio of these steroids differed markedly from that found in women. A great similarity of the follicular phase and the periovulatory period profiles was observed in both species for 17-hydroxyprogesterone, pregnenolone, androstenedione, estradiol and estrone. The pattern of. estradiol: estrone ratios was similar in both species. However, an elevation of the levels of the above five steroids, typical for the human luteal phase, was not found in baboons. The increase of testosterone values, seen in women at midcycle, was not detected in baboons. The plasma concentrations were lower in baboons than in humans of all the above steroids.Similarly to the findings in the human female, no cyclic variation was observed in the plasma levels of 17-hydroxypregnenolone, dehydroepiandrosterone and dihydrotestosterone. The mean concentrations, however, were significantly higher in baboons than in women for these three compounds.The plasma concentrations of the sulfates of pregnenolone and dehydroepiandrosterone were also estimated at different phases of the menstrual cycle. These measurements indicated that the concentrations in baboon plasma were considerably lower than in human plasma.In addition, LH levels were measured during the periovulatory period, using an in vitro bioassay. The sharp midcycle peak found in baboons exceeded that seen in the human.It is concluded that, with the exception of the luteal phase, the circulating steroid pattern in normally menstruating baboons resembles very closely that occurring in women.