Diurnal Variations in the Levels of Plasma and Urinary Androgens

Abstract

In 12 normal male subjects the urinary levels of testosterone, epitestosterone3 and 17-ketosteroids (17-KS) were determined for 6 consecutive 4-hr periods. In 5 of the subjects the levels of plasma luteinizing hormone (LH), testosterone and corticosteroids (CS) and urinary 17-hydroxycorticosteroids (17-OHCS) were also determined to compare with those of urinary testosterone, epitestosterone and 17-KS. Significant variations of plasma CS and testosterone, and urinary 17-KS, 17-OHCS, testosterone and epitestosterone were found. However, the magnitudes of the diurnal variations of plasma testosterone, and urinary testosterone and epitestosterone were much smaller than those observed for plasma CS and urinary 17-KS and 17-OHCS. In two of the 5 subjects there was a large change in the concentration of plasma LH during the day, whereas no change was observed in 3 other subjects. These data do not permit the conclusion that a diurnal variation of plasma testosterone is a result of changing LH levels. A significant correlation between the levels of urinary testosterone and 17-KS was observed at the same periods of the day. It would suggest that the observed diurnal variation of urinary testosterone might be the result of variations in plasma testosterone and other plasma steroids such as dehydroepiandrosterone (DHE) and androstenedione.