Metabolic Clearance Rate and Blood Production Rate of Testosterone and Androst-4-ene-3,17-dione Under Basal Conditions, ACTH and HCG Stimulation. Comparison with Urinary Production Rate of Testosterone

Abstract

Metabolic clearance rate, plasma concentration and blood production rate of testosterone and androstenedione, inter-conversion between blood testosterone and blood androstenedione, and urinary testosterone production rate have been studied in 2 normal adult male subjects under basal conditions, ACTH and HCG stimulation, and in 2 normal adult female subjects under basal conditions and ACTH stimulation. Under basal conditions blood testosterone production rate was 6.4 and 5.5 mg/day, blood androstenedione production rate 2.1 and 2.1 mg/day and urinary testosterone production rate 7.6 and 4.3 mg/day in the 2 male subjects; in the 2 female subjects these values were 0.37 and 0.27 mg/day, 2.7 and 3.6 mg/day and 0.8 and 0.9 mg/day, respect?ively. Under ACTH stimulation blood testosterone production rate decreased in the 2 male subjects and plasma testosterone concentration also decreased in 6 normal males studied. On the other hand, blood production rate of testosterone in females and of androstenedione in males and females increased. The disagreement between urinary and blood testosterone production rate in females was further accentuated when ACTH was given. In the 2 female subjects at least 50% of the blood testosterone production rate was accounted for by transformation of blood androstenedione to blood testosterone under both basal con?ditions and ACTH stimulation. HCG stimulation produced a sharp increase in blood testosterone production rate in the 2 male subjects, while blood androstenedione production increased in one and remained unchanged in the other subject.