[Circadian rhythm of hormonal activity of Macaca mulatta adrenal glands in hypokinesia].

The influence of the limited motion activity on circadian rhythm of cortisol. 11-desoxycortisol, 17-hydroxyprogesterone, 17-hydroxypregnenolone and aldosterone content in the blood plasma was studied in experiments on male Macaca rhesus monkeys. Under conditions of free behavior, the maximum steroid content in the blood plasma was seen early in the morning and minimum in the evening hours. The muscle activity restriction did not change the character of circadian variations but corticosteroid peak levels were markedly decreased after 7 days of hypokinesia in comparison with the control period. On the experiment prolongation the steroid content decreased throughout the whole day. The mean circadian cortisol, 11-desoxycortisol and aldosterone concentrations were significantly reduced following 2 weeks of hypokinesia. Potential mechanism of alterations mentioned and their relationships with circadian rhythms of other physiological systems under conditions of the restricted motion activity are discussed.