Catabolism of substance P in the stomach wall of the rat

Nigel W. Bunnett, Mark S. Orloff, Anthony J. Turner

Research output: Contribution to journalArticle

Abstract

The aim of this study was to examine the catabolism of substance P (SP) in the stomach wall of the rat. Catabolism in vitro was investigated by incubation of unlabelled and tritiated SP (prolyl 2,4-3,4(n)-3H SP) with membrane bound-peptidases prepared from the rat gastric corpus. Catabolism was studied in vivo by use of a catheter chronically implanted in the stomach wall to deliver tritiated SP to the gastric tissues and implanted dialysis fibers to collect the catabolic products. The products from both experiments were separated by high pressure liquid chromatography and identified by their retention times or amino acid analysis. Membrane-bound peptidases in vitro hydrolyzed both unlabelled and tritiated SP and the products of hydrolysis were consistent with the cleavage of three bonds : Gln6-Phe7, Phe7-Phe8 and Gly9-Leu10. None of the peptide fragments would be expected to be biologically active. Only those fragments would be expected to be biologically active. Only those fragments with tritiated Pro residues could be detected in vivo. The major identified products were SP(1-2) and SP(3-4), with smaller amounts of SP(1-4), SP(1-6), SP(1-7), SP(1-8) and SP(1-9). The enzymes that may be responsible for these cleavage patterns are discussed.

Original languageEnglish (US)
Pages (from-to)599-606
Number of pages8
JournalLife Sciences
Volume37
Issue number7
DOIs
StatePublished - Aug 19 1985

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

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