- An indicator of Lutenizing Hormone (LH) secretion
and Leydig cell function. Evaluate gonadal and adrenal function. Helpful
in the diagnosis of hypogonadism, hypopituitarism, Klinefelter syndrome
and impotence (low values) in males, and hirsutism, anovulation, amenorrhea,
and virilization in females, due to Stein-Leventhal syndrome, masculinizing
tumors of ovary such as Sertoli-Leydig cell tumor, tumors of the adrenal
cortex, and congenital adrenal hyperplasia (high values).
- Hirsutism in females is most commonly caused by
anovulation and excessive ovarian androgen production. Adrenal causes
are uncommon. Contemporary investigation for female hirsutism includes
dehydroepiandrosterone sulfate, 17-hydroxyprogesterone, and testosterone.
Testosterone is used in investigation of male precocious puberty. Male
pseudohermaphroditism includes defective testosterone synthesis, androgen
insensitivity syndromes, 5 alpha reductase deficiency, and testicular
- Methodology Immunochemiluminometric (ICMA)
- Additional Information
In males, testosterone may be normal or decreased in hypopituitarism,
including selective gonadotropin deficiency (eg, Kallmann syndrome).
It may be decreased with hepatic cirrhosis, estrogen therapy, and with
severe obesity. Low testosterone and high LH are encountered with renal
failure and in malnutrition. It is decreased with excessive alcohol
intake. Testosterone is usually increased in precocious puberty, related
to idiopathic or CNS lesion, or to adrenal tumors or congenital adrenal
- Testosterone exists in serum both free and bound
to albumin and to sex hormone binding globulin (SHBG) (testosterone
binding globulin). Unbound (free) testosterone is the active moiety.
Free as well as total testosterone can be measured. Usual testosterone
assays measure both bound and unbound levels. In certain settings, total
testosterone can be normal but free testosterone increased, or the reverse;
then the total testosterone result is misleading.
- The major androgens of normal females include
dehydroepiandrosterone (DHEA) and androstenedione, both weak androgens.
Both are derived from adrenal glands as well as gonads, and can be converted
to testosterone. About half of the testosterone in a female is derived
from peripheral conversion of androstenedione.
- Lutenizing Hormone (LH) stimulates androgen production.
Adrenalcorticotropic Hormone (ACTH) and Thyroid Stimulating Hormone
(TSH) deficiencies are more likely the cause of secondary testicular
failure than is an LH decrease. Low LH with low testosterone are evidence
of a pituitary lesion.
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