Related tests: free testosterone, total testosterone, DHEA-S, LH, FSH
Clinical significance
Androstenedione (or Δ4-androstenedione) is a steroid hormone produced in the adrenal glands and gonads as an intermediate in the biochemical pathway that makes testosterone, oestrone and oestradiol. It is the common precursor of male and female sex hormones. Androstenedione secreted into the plasma can be converted by peripheral tissues into testosterone and oestrogens.
Androstenedione has relatively weak androgenic activity, estimated at about 20% of the activity of testosterone.
In premenopausal women the adrenal glands and ovaries each produce about half of the total androstenedione (about 3 mg/day).
After the menopause androstenedione production halves again, because the ovaries produce less. Even so, androstenedione remains the main steroid produced by the ovaries after the menopause.
Clinical indications
Serum androstenedione gives an index of androgen biosynthesis.
Sample type
The patient must have a blood sample taken.
Preparation
You must fast for at least 8 hours; a small amount of water is allowed. You must have been standing or sitting upright for at least 30 minutes.
Notes
High androstenedione levels have been found in congenital adrenal hyperplasia, polycystic ovary, hirsutism in women and adrenal and ovarian tumours.