••• Chapter 58^ Hyperandrogenism^577
❍ What are the metabolic excretory products of testosterone?
17-ketosteroids.
❍ In ovulatory women, which ovarian cell types are involved in androstenedione (1) secretion and (2)
conversion to estrone and estradiol, and which (3) hormone is directly involved in stimulating this cascade?
(1) Theca cells, (2) granulosa cells, and (3) luteinizing hormone (LH).
❍ What happens to LH pulse frequency and amplitude in patients with PCOS?
They are increased.
❍ Which enzyme is involved in the conversion of androstenedione to estrogens, and what is the activity level
of this enzyme in PCOS and the resulting effects?
Aromatase, which is deceased, and as a result excessive amounts of androstenedione are secreted into the
circulation, which can be converted peripherally to testosterone by most tissues.
❍ Which hormone stimulates the granulosa cells to produce aromatase that converts androgen to estrone and
estradiol?
Follicle-stimulating hormone (FSH).
❍ True or False: The low or normal FSH levels found in patients with PCOS are due to increased inhibin
levels.
False. Inhibin levels are not increased in patients with PCOS.
❍ Anovulation and follicular atresia seen in patients with PCOS results from?
High androgen levels inhibiting aromatase activity, and an androgen dominant microenvironment ensues in the
follicle inhibiting further maturation.
❍ Dehydroepiandrosterone sulfate (DHEA-S) is exclusively secreted from which gland?
Adrenal.
❍ What is the normal circulating range of DHEA-S in women?
Ranges are dependent on age and each individual laboratory but typically range from 100 to 350 μg/dL.
❍ What is the active form of testosterone and what enzyme converts testosterone to its active form?
Dihydrotestosterone and 5a-reductase.
❍ What is the effect of insulin-like growth factor 1 (IGF-1) on the enzyme 5a-reductase?
5 a-Reductase activity is increased. In anovulatory patients with insulin resistance and hyperinsulinemia, this can
intensify hirsutism.
❍ What is the metabolite of dihydrotestosterone that reflects 5a-reductase activity?
3 a-Androstanediol glucuronide (3a-AG).