Why this test?
For the diagnosis of virilizing syndromes: polycystic ovary syndrome;
Cushing's syndrome; congenital hyperplasia of the adrenal cortex;
androgen-producing tumors of the ovaries, testicles or adrenal adenomas / carcinomas.
To control the treatment of such syndromes.
In what cases is it prescribed?
When examining a patient with signs of hyperandrogenism: with hirsutism (hair growth above the upper lip, on the chin, on the white line of the abdomen), severe acne, changes in the timbre of the voice, clitoromegaly, an increase in muscle mass.
When examining a baby with signs of a violation of gender differentiation: with external genitalia that have both female and male features.
Do not take oral contraceptives for 30 days before the testing .
Exclude physical and emotional overstrain within 72 hours before the testing.
Androstenedione is a precursor of the sex hormones testosterone and estrone, which is formed in the Leydig cells of the testicles, theca cells of the ovaries, and also in the reticular zone of the cortical substance of the adrenal glands in people of both sexes. Further conversion of androstenedione into testosterone occurs in the cells of peripheral tissues (mainly in the gonads).
Despite the fact that normally the effect of androstenedione is inferior to the effect of other male sex hormones (primarily testosterone), its importance increases with the development of virilizing syndromes. Measurement of androstenedione concentration is used for differential diagnosis and control of treatment of these diseases. In addition, weak androgens play a leading role in the metabolism of patients with a low concentration of testosterone in the norm (for example, boys before puberty). Androstenedione is also the main steroid hormone of postmenopausal women.
The analysis for androstenedione is carried out during the examination of patients with signs of hyperandrogenism: acne, hirsutism (hair growth of the male type: above the upper lip, on the chin, along the white line of the abdomen), change in voice timbre, clitoromegaly.
The most common causes of such virilization are: hyperproduction of androgens by the ovaries (polycystic ovary syndrome, hyperthecosis, and androgen-producing tumor) and hyperproduction of adrenal androgens (Cushing's syndrome, adenoma, or adrenal carcinoma), as well as the use of certain medications (danazol, anabolic steroids) and some other hormonal disorders (hyperprolactinemia, hypothyroidism). Since androstenedione is produced by both adrenal and gonad cells, this study is not applicable for differential diagnosis of the cause of virilization.
Therefore, with a high level of androstenedione, additional laboratory and instrumental studies are conducted to establish the source of increased androgen secretion. Determination of the level of androstenedione is indicated when congenital hyperplasia of the adrenal glands is suspected in infants and young children.
These relatively rare syndromes of steroid hormone synthesis enzyme deficiency (most often 21-beta-hydroxylase, a more rare variant - 11-beta-hydroxylase) are characterized by insufficient production of aldosterone and cortisol, but a significant increase in the level of dehydroepiandrosterone, androstenedione and testosterone. In the clinical picture of congenital hyperplasia of the adrenal glands, the symptoms of hyperandrogenism prevail: the presence in a genetically female child of external sexual structures with both female and male characteristics.
The sensitivity of the test for the diagnosis of virilizing syndromes is maximum when examining samples with a high content of androstenedione and decreases when examining samples obtained from patients with a low concentration of androgens (children, women in the postmenopausal period, men with primary hypogonadism).
The test is characterized by high specificity (approaching 100%), however, cross-reaction of reagents with some other androgens (dehydroepiandrosterone sulfate and dihydrotestosterone) is possible, which can lead to higher indicators. Like other sex hormones, a large part of androstenedione is in blood serum in a bound state (conjugated, sulfated, linked to androgen-globulin), that is, inactive.
The share of the active hormone depends on the physiological state of the body, taking some medications, and the presence of concomitant pathology.
Normally, only a third of the total amount of androstenedione is present in the free state and is responsible for the effects manifested in the target organs. The study allows you to determine the total amount of androstenedione in blood serum, while the active and bound fraction of the hormone is not evaluated separately. In addition, the effects of androstenedione can be modified when this hormone interacts with other androgens and antiandrogens at the level of binding to specific receptors.
Therefore, the test result does not always correlate with the severity of the clinical manifestations of hyperandrogenism. In other words, the study allows you to assess the concentration of the hormone, but not its bioactivity in the body. Interpretation of the analysis results should be carried out taking into account additional laboratory data on the patient's hormonal background.