Effects of a transplantable insulinoma upon regulatory peptide concentrations in the gastrointestinal tract of the rat

J. M. Conlon, C. F. Deacon, C. J. Bailey, P. R. Flatt

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9 Citations (Scopus)

Abstract

The rapid growth (0.8±0.3 g/day) of a transplantable insulinoma, which also contained substance P (2.9±2.3 pmol/g) and gastrin-releasing peptide (3.2± 2.1 pmoll/g), resulted in the development of hyperphagia, hyperinsulinaeinia and hypoglycaemia in rats (n=8). After a 14-day growth period, the insulinoma-bearing rats showed an increase (49%; p<0.01) in the weight of the small intestine but no significant change in stomach weight compared with control animals. The content (pmol/organ) of somatostatin, substance P, neurokinin A and vasoactive intestinal peptide in the stomachs of the tumour rats was unchanged. A depletion in the content (53% p<0.01) and concentration (57%; p<0.01) of gastrin-releasing peptide, however, suggested either hypersecretion, possibly mediated through hypoglycaemia-induced vagal stimulation, or inhibition of synthesis. The concentration and content of glucagon-like immunoreactivity (enteroglucagon) in the small intestine of the insulinoma rats increased markedly (47%; p<0.01 and 120%; p<0.01). This increase is consistent with a proposed role of this peptide as a factor trophic to the intestinal mucosa. No significant changes in the concentrations of somatostatin, substance P, neurokinin A, vasoactive intestinal peptide and gastrin-releasing peptide in the small intestine were observed. However, the increase in gut weight resulted in a greater content of vasoactive intestinal peptide (40%; p<0.01) and substance P (37%; p<0.05) in the insulinoma rats.

Original languageEnglish
Pages (from-to)334-338
Number of pages5
JournalDiabetologia
Volume29
Issue number5
DOIs
Publication statusPublished - May 1986
Externally publishedYes

Keywords

  • Insulinoma
  • enteroglucagon
  • gastrin-releasing peptide
  • neurokinin A
  • somatostatin
  • substance P
  • vasoactive intestinal polypeptide

ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism

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