Is crustacean hyperglycaemic hormone precursor-related peptide a circulating neurohormone in crabs?
Sites of synthesis and release patterns of crustacean hyperglycaemic hormone precursor-related peptide (CPRP) were investigated with those of crustacean hyperglycaemic hormone (cHH), in order to determine whether this precursor-related peptide satisfies certain criteria necessary for its definition as a secretable, circulating hormone. Using the edible crab, Cancer pagurus, sites of CPRP synthesis were determined by immunohistochemistry and release patterns of both peptides were determined in vivo and in vitro by radioimmunoassay of haemolymph and eyestalk superfusates. Both peptides were co-released from sinus glands (SGs) following potassium-evoked depolarization of isolated eyestalk preparations. However, stress-evoked in vivo release resulted in apparent non-stoichiometric circulating peptide profiles. This phenomenon is explained by notable differences in clearance rates of the peptides in haemolymph. In contrast to cHH, CPRP is very slowly degraded in vivo. Although CPRP is clearly a circulating peptide, whose release is concomitant with that of cHH, physiologically pertinent roles for this molecule remain to be discovered.
Wilcockson
David C
DC
School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton, Hampshire, SO16 7PX, UK. d.c.wilcockson@soton.ac.uk
Chung
Sook J
SJ
Webster
Simon G
SG
D000818:Animals; D060829:Arthropod Proteins; D003386:Brachyura / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D006207:Half-Life; D006458:Hemolymph / Q000737:chemistry*; D007150:Immunohistochemistry; D007447:Invertebrate Hormones / Q000096:biosynthesis / Q000097:blood; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000097:blood*; D018377:Neurotransmitter Agents / Q000097:blood*; D011498:Protein Precursors / Q000096:biosynthesis / Q000097:blood*; D015203:Reproducibility of Results
D060829:Arthropod Proteins; D007447:Invertebrate Hormones; D009419:Nerve Tissue Proteins; D018377:Neurotransmitter Agents; D011498:Protein Precursors; C015947:hyperglycemic hormone, crustacean; C061766:hyperglycemic hormone precursor, crustacean