|Luteinizing hormone, beta subunit|
|Properties of human protein|
|Mass / length primary structure||92 + 121 = 213 amino acids (α + β)|
|Secondary to quaternary structure||LH = LH-α + LH-β|
|Gene names||; LSHB|
|ATC code||G03 GA07|
The luteinizing hormone , or luteinizing hormone ( LH ) ( "gelbfärbendes hormone" of Latin luteus , "with Reseda colored", "orange yellow", from the Greek lotus : Yellow, for example egg yolk) or lutropin is in the pituitary gland is formed and one of the Hormones that help regulate reproduction. In women, it promotes ovulation and the formation of the corpus luteum (luteinization). In men it is also called interstitial cell stimulating hormone (ICSH) . It is in both sexes together with the follicle stimulating hormone involved (FSH) in the maturation and production of sex cells: ovulation ( ovulation ) in women or sperm maturation in the male.
The glycoprotein LH consists of two subunits, the α-subunit ( α-LH ) with 92 amino acids and the β-subunit (β-LH) with 121 amino acids. The β subunit is specific for the LH. The α subunit, on the other hand, is also found in other hormones: follicle-stimulating hormone (FSH), human chorionic gonadotropin (hCG) and thyrotropin (TSH).
In men, the luteinizing hormone stimulates the production of testosterone (the male sex hormone which, together with the follicle-stimulating hormone, triggers the production of sperm) in the Leydig cells between the testicles. In women, in whom the luteinizing hormone, together with the follicle-stimulating hormone, stimulates the ovary to release estrogen , a steep increase in the LH concentration in the blood can be detected before ovulation, stimulates the release of an egg from the ovary and then quickly decreases again . If, for example, due to an illness, there is reduced or no LH release, pregnancy is not possible.
LH increases androgen synthesis (especially androstenedione ) in the theca cells (the outer cell layer around a follicle) of the ovary, which in the granulosa cells (the inner cell layer around the follicle) by the enzyme aromatase (cytochrome P450 dependent monoxygenase 19; CYP19A1) in Is converted to estradiol . LH thus indirectly increases estrogen production.
In ferrets, LH receptors are also found in the adrenal cortex . High LH levels after castration lead to the production of the sex hormones estradiol, 17-hydroxyprogesterone and androstenedione in the adrenal cortex and thus to adrenal disease .
An LH test , also known as an ovulation test , is used to determine the time of ovulation (also called follicle rupture or ovulation, at which the follicle bursts and the egg cell is released into the fallopian tube) and thus to determine the fertile days of the woman. With this knowledge, it is possible to plan the timing of sexual intercourse and thus increase the likelihood of pregnancy. This test uses monoclonal antibodies against LH to selectively detect elevated levels of LH.
- Lois Jovanovic, Genell J. Subak-Sharpe: Hormones. The medical manual for women. (Original edition: Hormones. The Woman's Answerbook. Atheneum, New York 1987) From the American by Margaret Auer, Kabel, Hamburg 1989, ISBN 3-8225-0100-X , pp. 65 ff., 88 ff., 139 ff. And 380