Hormonal function of sexual glands and adrenals in monkeys of different age

Abstract

The levels of bioactive LH, major sex and adrenal steroid hormones and their precursors in the system of biosynthesis were measured in the peripheral blood of 37 male Papio hamadryas of different age under baseline conditions and after injection of ACTH, LH releasing hormone, and human chorionic gonadotropin. The measurements were carried out in adult animals with the optimal reproductive characteristics (group 1, aged 6 to 9, and group 2, aged 10 to 15 years) and in aging males (group 3, aged 20 to 26 years). The levels of hydrocortisone and its immediate precursor in the biosynthesis chain of 11-deoxyhydrocortisone virtually did not change with age, whereas the concentrations of ∆5-precursors (pregnenolone and 17-hydroxypregnenolone) gradually reduced with aging. The levels of the major adrenal androgens dehydroepiandrosterone and dehydroepiandrosterone sulfate also appreciably decreased with age. The levels of sex hormones did not change between 6 and 15 years of age; but in animals aged 20 to 26 the concentration of testosterone showed a trend to reduction, and that of LH to increase. In group 3 the peaks of LH and testosterone secretion in response to LH releasing factor were delayed. On the other hand, the amplitude and duration of the increment of both LH and testosterone in response to LH releasing factor was virtually unchanged at all ages and was largely determined by the basal level of LH. The detected age-specific changes in the hormonal function of adrenals and sex glands of Papio hamadryas are much similar to those in humans.