Androstenedione

General Information

Androstenedione (also known as D4-androstenedione)is a steroid which serves as a major precursor for the androgen testosterone and oestrogens oestrone and oestrodiol. Its clinical interest derives from the fact that it is often elevated in cases of abnormal hair growth (hirsutism) and virilization. Unlike the adrenal androgens dehydroepiandrosterone and its sulphate, circulating androstenedione originates both from the adrenals and from the ovaries. The production of adrenal androstenedione is governed by ACTH, while production of gonadal androstenedione is under control by gonadotropins. Plasma levels increase steadily from about the seventh year of life. In premenopausal women the adrenal glands and ovaries each produce about half of the total androstendione (about 3 mg/day). After menopause androstenedione production is about halved, primarily due to the reduction of steroid secreted by the ovary. Androstenedione exhibits a diurnal variation, being highest in the morning, and also a cyclical variation during the menstrual cycle, being highest near mid-cycle. During pregnancy, there is an increase in the plasma level.