Chapter 76 - Crustacean hyperglycemic hormone

Abstract

Crustacean hyperglycemic hormone (CHH) is produced by the X-organ sinus gland complex in the eyestalk. CHH is a hyperglycemic factor and then regulates the hemolymph glucose homeostasis in the crustacean. Because CHH is a most-abundant neuropeptide in the sinus gland, many CHHs have been identified from decapod, isopod, and stomatopod species. The primary structure of CHH is similar to three other eyestalk hormones, the molt-inhibiting hormone (MIH), the vitellogenesis-inhibiting hormone (VIH), and the mandibular organ-inhibiting hormone (MOIH). Therefore, CHH, MIH, VIH, and MOIH form a CHH-family. Most CHH family peptides consist of 72–78 aa residues and have six conserved cysteine residues that form three intrachain disulfide bonds. MIH inhibits the synthesis of ecdysteroids, which are molting hormones in the crustacean. VIH inhibits the synthesis of vitellogenin, which is a precursor of the major yolk protein, vitellin. MOIH inhibits the synthesis of methyl farnesoate, which is known as an innate juvenile hormone in crustaceans.