Secretagogue activities in cod (Gadus morhua) and shrimp (Penaeus aztecus) extracts and alcalase hydrolysates determined in AR4-2J pancreatic tumour cells

Peptides with gastrin immunoreactivity were measured in cod muscle (Gadus morhua) and shrimp heads (Penaeus aztecus) extracts and alcalase hydrolysates and separated by two chromatographic steps. Secretagogue activities present in crude extracts fractions were examined with or without specific antagonists of CCK receptors in AR4-2J cells. Several sub-fractions significantly stimulate amylase release, up to 110%. These stimulatory effects could be completely inhibited by the presence of L 365, 260 specific antagonist of CCKB receptors. After hydrolysis of the raw material, the samples were partially fractionated by two chromatographic steps and potential active fractions detected by a gastrin-CCK radioimmunoassay. The molecular masses of the active fractions were lower than for the extracts. Stimulation of amylase release was higher than with extracts, and the inhibition by L 365, 260, less pronounced. These results show that some peptides remaining after hydrolysis or extraction still exert biological activities and have to be tested in nutritional studies. (C) 2003 Elsevier Science Inc. All rights reserved.