Gastrin/cholecystokinin-like post-prandial variations: quantitative and qualitative changes in the haemolymph of penaeids (Crustacea Decapoda)

Summary Gastrin/cholecystokinin-like (G/CCK) peptides from the haemolymph of two penaeidsPenaeus japonicus andP. stylirostris (Crustacea, Decapoda) were characterized by gel filtration. In starved shrimps, four classes of peptides were found. One fraction elutes in the void volume, a second has a molecular weight around 5 kDa, a third between 1 and 2.5 kDa, and the fourth fraction is composed of very small peptides. Differences exist between the two species concerning the relative proportion of each molecule.After a meal, there is a two-fold increase of total G/CCK-like peptides and marked qualitative changes are described. Briefly, high molecular weight fractions decrease while low molecular ones increase. After 5 h a return to the initial concentrations is observed. These changes are more pronounced inP. stylirostris. Such variations suggests a role for these peptides in regulation of crustacean digestive processes.