Meeting Abstract

11.1  Jan. 4  Identification of CHH-b functions of the lobster Homarus americanus LAUFER, Hans*; DEMIR, Neslihan; BAGSHAW, Joseph; Univ. of Connecticut, CT; Univ. of Connecticut, CT; Worcester Polytech Inst., MA laufer@uconn.edu

Crustacean hyperglycemic hormones (CHHs) are members of a family of neuropeptides that inhibit other hormones. The main function of CHHs is to regulate hemolymph glucose, but they also inhibit reproduction by gonad-inhibiting hormones (GIHs) or vitellogenesis-inhibiting hormones (VIHs); mandibular organ-inhibiting hormones (MOIHs) control methyl farnesoate (MF) synthesis which regulate morphogenesis, and metamorphosis; molting is inhibited by molt inhibiting hormones (MIHs). Other CHH functions include androgenic gland inhibition, stress responses, osmoregulation, hydromineral regulation, and secretion of digestive enzymes. Lobsters have two CHH isoforms (CHH-A and CHH-B) which may have different targets and functions. Our goal was to determine the function of pure eyestalk recombinant hyperglycemic hormone-B (CHH-B). The gene encoding H.americanus CHH-B was constructed and expressed in Pichia pastoris yeast cells. The supernatants from cultures expressing CHH-B were tested for biological activity and compared to sinus gland extracts (0.4-1 SG equivalents). Recombinant CHH-B resulted in decreased methyl farnesoate (MF) synthesis, demonstrating MOIH activity; increased CHH activity; decreased vitellogenin synthesis, VIH activity or GIH activity, and androgenic gland-inhibiting activity; decreased ecdysone production, MIH activity was also found. Our results show that CHH-B is one multifunctional member of the CHH neuropeptide family, with a minimum of 5 different endocrinological functions. (Supported in part by the Sea Grant College Program, NOAA, and the CT Department of Environmental Protection’s Long Island Sound Research Fund).