[Circadian rhythms of androgen levels in the blood of male hamadryas baboons].

Radioimmunoassay was used to investigate circadian rhythms of blood plasma testosterone, 5 alpha-dihydrotestosterone, androstendione and dehydroepiandrosterone in intact animals and in those preadapted for experimental conditions. Blood plasma of monkey demonstrated monophasic circadian rhythms in the levels of androstendione, dehydroepiandrosterone and 5 alpha-dihydrotestosterone, with the maximal values seen early in the morning and minimal values in the evening. Circadian rhythms of testosterone were opposite in character. The adaptation of monkeys for housing and experimental conditions was marked by an increase in testosterone and 5 alpha-dihydrotestosterone levels in the blood as well as by an insignificant elevation of the levels of androgens of adrenal origin, leading to the changes in circadian rhythms of steroid hormones.