CLONING AND EXPRESSION OF 2 MESSENGER-RNAS ENCODING STRUCTURALLY DIFFERENT CRUSTACEAN HYPERGLYCEMIC HORMONE PRECURSORS IN THE LOBSTER HOMARUS-AMERICANUS

The crustacean hyperglycemic hormone (CHH) of the X-organ sinus gland complex is a multifunctional neurohormone primarily involved in the re gulation of blood sugar levels. HPLC analysis of lobster sinus glands revealed two CHH-immunoreactive groups, each consisting of two isoform s with identical amino acid sequences and molecular weights. In order to obtain more information concerning the number and sequences of prep roCHHs, and to study their expression, we isolated two full-length cDN As encoding two different CHH preprohormones. Both preprohormone struc tures consist of a signal peptide, a CHH-precursor-related peptide and a highly-conserved CHH peptide. Expression studies revealed that the X-organ is not the only source of CHH mRNA because the ventral nerve s ystem also expresses this mRNA. Based on these findings and earlier st udies on the effect of eyestalk ablation, implantation of thoracic/abd ominal ganglia as well as the multifunctionality of CHH, we postulate that CHH, present in the ventral nerve system is a good candidate for a supplementary role in the control of reproduction and molting.