Elimination of porcine heptadecapeptide gastrin (G17) and human leu big gastrin (G34) by the perfused pig liver.

Abstract

In order to study some of the molecular events during the hepatic passage of gastrin, we perfused sulfated natural porcine gastrin (G17 II) through isolated pig livers. The disappearance half time of G17 II was about 20-30 min when the starting gastrin concentrations were greater than 100 pM; lower concentrations were reduced with half times of 40-100 min. Synthetic human leu-32 (G34) was not eliminated. The use of region-specific antibodies to gastrin indicated that degradation was more effective at the N-terminus of gastrin. Whereas Sephadex chromatography revealed no change of the molecular size, SDS-polyacrylamide gel electrophoresis showed the presence of smaller immunoreactive fragments of gastrin in addition to immunoreactive fragments of gastrin of the heptadecapeptide size. These findings indicate that the isolated porcine liver degrades porcine G17 to smaller fragments.