Biological Chemistry - Berezov T. T., Korovkin B. F. 1998

Hormones
Pituitary Hormones
Gonadotropic hormones (gonadotropins)

Gonadotropins include follicle-stimulating hormone (FSH, follitropin) and luteinizing hormone (LH, lutropin), also known as interstitial Cell-stimulating hormone*. Both Hormones are synthesized in the anterior Pituitary Gland and, like thyrotropin, are complex Proteins—Glycoproteins with a Molecular Weight of 25,000. They regulate steroidogenesis and gametogenesis in the Gonads. Follitropin stimulates ovarian follicle maturation in females and Spermatogenesis in males. Lutropin stimulates the secretion of estrogens and progesterone in females, as well as follicle rupture leading to corpus luteum formation, while in males it stimulates testosterone secretion and The Development of interstitial tissue. As noted previously, The Biosynthesis of gonadotropins is regulated by the hypothalamic hormone gonadotropin-releasing hormone (gonadoliberin).

The Chemical Structure of the lutropin molecule has been completely elucidated. Lutropin consists of two subunits, α and β. The structure of the α-subunit is identical in most animals. For instance, in sheep, it contains 96 amino acid residues and 2 carbohydrate moieties. In humans, the α-subunit is shorter by 7 amino acid residues at the N-terminus and differs in The Nature of 22 Amino Acids. The Amino Acid Sequence in the β-subunits of porcine and human lutropin has also been determined. Neither the α- nor the β-subunit possesses biological activity on its own (much like most enzyme subunits). Only their complex—The formation of which is most likely predetermined by their Primary Structure—results in a biologically active macromolecular structure driven by hydrophobic interactions.