Testosterone

Latest Edit: Iva Lloyd, ND 2015-07-31 (EDT)

See Also	Lab Tests

Testosterone levels are used to evaluate ambiguous sex characteristics, precocious puberty, virilizing syndromes in females and infertility in males.

Discussion

• Testosterone is a hormone made by the Leydig cells in the testicle.

• Dehydroepiandrosterone (DHEA) is the precursor of androstenedione which is the precursor of testosterone and estrogen.

• Testosterone is responsible for stimulating spermatogenesis as well as influencing the development of male secondary sexual characteristics.

• Testosterone, the dominant testicular androgen, is the precursor to 5-dihydrotestosterone (DHT). The androgenic effect in various tissues is not exerted by testosterone but by the locally produced DHT.

• Dihydrotestosterone (DHT) is the most potent androgen; it is three to five times more potent than testosterone. DHT is derived partially by direct secretion from the testes, but mostly by conversion from testosterone and other androgens in target tissues (scalp, skin, prostate, liver and others) from five alpha reductase enzyme activities.

• Overproduction of testosterone in young males will therefore cause precocious puberty. Whereas overproduction of this hormone in females will cause masculinization, which presents as amenorrhea or absence of menstrual bleeding in a woman of reproductive age, as well as the excessive growth of body hair, known as hirutism.

• Testosterone levels are generally used to evaluate ambiguous sex characteristics, precocious puberty, virilizing syndromes in the female, and infertility males.

Article	Treating Hypogonadism in Infertile Men, NDNR; 2012 August

• This test can also be used as a tumor marker for rare tumors of the ovary and testicle.
• Ovarian and adrenal tumors and medications such as danazol are all potential causes of masculinization in the female while reduced levels of testosterone in the male suggest hypogonadism or klinefelter's syndrome.

• Testosterone levels are inversely related to coronary artery disease. Low testosterone can contribute to increase calcium in the arteries.

Patient Preparation

• No fasting is required.

• Factors which can cause increased levels

• Medications such as anticonvulsants, barbituates, estrogens and oral contraceptives
• alcohol consumption

• Factors which can cause decreased levels

• Medications such as androgens, dexamethasone, diethylstilbestrol, digoxin, steroids, ketoconazole, phenothiazine, spironolactone
• alcohol consumption

Clinical Implications

High levels indicate:

• Males:

• Idiopathic sexual precocity
• Pinealoma
• Encephalitis
• Congenital adrenal hyperplasia
• Adrenocortical tumor
• Testicular or extragonadal tumor
• Hyperthyroidism
• Testosterone resistance syndromes

• Females:

• Ovarian tumor
• Adrenal tumor
• Congenital adrenocortical hyperplasia
• Trophoblastic tumor
• Polycystic ovarian syndrome
• Idiopathic hirsutism

Low levels indicate:

• Males

• Klinefelter's syndrome
• Cryptorchidism
• Primary and secondary hypogonadism
• Down's syndrome
• Orchidectomy
• Hepatic cirrhosis

Associated Tests

• Androstenedione