Daily variation of serum cortisol, 17-hydroxyprogesterone and five androgens in healthy women.

Serum cortisol, 17-hydroxyprogesterone and five androgens (androstenedione, 11-hydroxyandrostenedione, dehydroepiandrosterone and its sulphate, and testosterone) were measured by radioimmunoassay at 8:00, 16:00, 20:00 and 24:00 h and again at 8:00 h on the next day in eight healthy female subjects aged 16-40 years in the midfollicular phase of the menstrual cycle. Regression analysis revealed a significant (alpha = 0.05) circadian periodicity, with estimated peaks between 8:00 a.m. (testosterone) and 2:00 p.m. (dehydroepiandrosterone sulphate), and with estimated amplitudes between 76% (11-hydroxyandrostenedione) and 33% (17-hydroxyprogesterone, testosterone and dehydroepiandrosterone sulphate) of the rhythm adjusted mean. The inferential statistical approach illustrated here should contribute significantly to the diagnostic elucidation of adrenocortical disorders.