Degradation of endogenous heptadecapeptide gastrin by endopeptidase 24.11 in the pig

D. M. Power, N. Bunnett, A. J. Turner, R. Dimaline

Research output: Contribution to journalArticlepeer-review

Abstract

Hydrolysis of heptadecapeptide gastrin (G-17) by endopeptidase 24.11 (EC 3.4.24.11) was studied in vivo and in vitro in the pig. Ion exchange chromatography and radioimmunoassay with three region-specific antisera were used to identify the products of porcine G-17 degradation. Incubation of antral extracts with pure endopeptidase 24.11 resulted in a substantial loss of intact G-17: 80% C-terminal immunoreactivity was lost in 60 min. This hydrolysis was completely inhibited by phosphoramidon, which is a specific inhibitor of endopeptidase 24.11. In antral extracts G-17 accounted for > 95% of total C-terminal immunoreactivity, compared with < 60% C-terminal immunoreactivity in the gastric venous outflow; shorter C-terminal forms comprised the major part of the remaining immunoreactivity. After infusion of phosphoramidon, the concentration of intact G-17 was increased, and there was a corresponding reduction in the concentration of other C-terminal immunoreactive fragments. We conclude that endopeptidase 24.11 degrades G-17 in vitro and in vivo and may be responsible for the generation of C-terminal fragments from G-17 after secretion from the porcine antral mucosa.

Original languageEnglish (US)
Pages (from-to)G33-G39
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume253
Issue number1 (16/1)
DOIs
StatePublished - 1987

ASJC Scopus subject areas

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)

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