Changes in peripheral blood levels of steroid hormones and their precursors inPapio hamadryas under stress

The character of changes in the level of 12 steroids in peripheral blood plasma of male baboons (Papio hamadryas) under conditions of immobilization and surgical stress was determined by a radioimmunological method. During stress the concentration of androgens in the blood plasma of the monkeys is reduced, whereas the concentration of precursors of the steroid hormones and of hydrocortisone is increased. These changes are opposite in phase to the diurnal rhythm of the steroids. The fall in the levels of testosterone and dihydrotestosterone and the rise in the concentrations of pregnenolone, 17 α-hydroxypregnenolone, and 17 α-hydroxyprogesterone in the blood plasma of male baboons exposed to stress were found to be the most objective and sensitive criteria of the stressor situation.