Luteinizing Hormone (LH) – 004283

LH (luteinizing hormone), together with FSH (follicle-stimulating hormone), belongs to the gonadotropin family. LH and FSH regulate and stimulate the growth and function of the gonads (ovaries and testes) synergistically.^2-4 Like FSH, TSH, and hCG, LH is a glycoprotein consisting of two subunits (α- and β-chains). This proteohormone, which consists of 121 amino acids³ and three sugar chains, has a molecular weight of 29,500 daltons.⁴

In women, the gonadotropins act within the hypothalamus-pituitary-ovary regulating circuit to control the menstrual cycle.^5,6 LH and FSH are released in pulses from the gonadotropic cells of the anterior pituitary and pass via the bloodstream to the ovaries. Here the gonadotropins stimulate the growth and maturation of the follicle and hence the biosynthesis of estrogens and progesterones. The highest LH-concentrations occur during the midcycle peak and induce ovulation and formation of the corpus luteum, the principal secretion product of which is progesterone.