Mode of action of the crustacean hyperglycemic hormone

Abstract

Glucose levels in crayfish hemolymph are enhanced by the crustacean hyperglycemic hormone (CHH); at present there is some evidence that this action is mediated by cyclic nucleotides. CHH is capable of stimulating adenylate cyclase in the abdominal muscle. There is an increase in cyclic AMP and cyclic GMP contents in hepatopancreas and abdominal muscle after CHH injection. Cyclic nucleotides are able to evoke the same reaction as CHH in vivo and in vitro. Cyclic nucleotide-dependent protein kinases are activated by the hormone, which leads to a phosphorylation and therefore inhibition of glycogen synthase. So far, an effect of purified hormone on phosphorylase and phosphorylase kinase has not been demonstrated in the abdominal muscle. © 1985 the American Society of Zoologists.