Androstenedione in blood (chromatography)
Androstenedione is a key precursor of testosterone and estrone in human hormone metabolism, determined for the diagnosis of virilising conditions: polycystic ovaries, glandular and adrenal tumours (including Cushing's syndrome), and congenital hyperplasia of the adrenal cortex. It is an indicator for signs of excessive masculinisation, such as acne, increased facial and body hair growth (hirsutism), changes in voice pitch and enlarged clitoris.
The main causes of virilization include:
- Excessive production of androgens by the ovaries: polycystic ovaries, hypertecocytosis or tumors with hormonal activity.
- Increased secretion of adrenal androgens: Cushing's syndromes, adrenal adenomas and carcinomas.
- The use of medications (danazol, anabolic steroids).
- Hormonal disorders like hyperprolactinaemia or hypothyroidism.
Androstenedione is synthesized in both the gonads and the adrenal glands, which makes it difficult to use it to accurately locate the source of excessive androgenic effects. In such cases, additional studies (biochemical analyses, instrumental diagnostics) are required.
The determination of androstenedione levels is of particular importance when congenital adrenal hyperplasia is suspected in newborns and infants. These rare conditions are caused by mutations in genes encoding steroid synthesis enzymes (most commonly 21-beta-hydroxylase), resulting in deficiencies in aldosterone and cortisol with concomitant increases in concentrations of dehydroepiandrosterone, androstenedione, and testosterone. It is clinically manifested as hyperandrogenism in infants of female genetic sex — the presence of mixed (male) characteristics on the external genitalia.
Thus, androstenedione level analysis plays a central role in identifying and understanding various conditions with excessive masculinization. Important symptoms of congenital adrenal hyperplasia are manifestations of hyperandrogenism, including the presence of external genitalia with both female and male characteristics in an infant of female genetic sex.
Elevated levels are observed in:
- polycystic ovary syndrome;
- neoplasms of the genital glands and adrenal glands;
- Icenko-Cushing's syndrome;
- congenital hyperplasia of the adrenal cortex;
- Alzheimer's disease;
- the usual miscarriage of pregnancy.
A decrease in the level is observed when:
- age-related decrease in sexual function;
- sickle cell anemia;
- hypofunction of the adrenal cortex;
- osteoporosis.