Effects of hypoglycemia and prolonged fasting on insulin and glucagon gene expression. Studies with in situ hybridization

L. Chen, I. Komiya, L. Inman, J. O'Neil, M. Appel, T. Alam, Roger H Unger

Research output: Contribution to journalArticle

40 Scopus citations

Abstract

In situ hybridization of proinsulin and proglucagon mRNA was performed in rat pancreas to assess prohormone gene expression during various glucopenic conditions. During a 4-d fast mean blood glucose declined by 48 mg/dl; proinsulin mRNA signal density remained normal while proglucagon mRNA signal density more than doubled. At the end of a continuous 12-d insulin infusion blood glucose averaged 53 ± 12 mg/dl; proinsulin mRNA signal density declined to 30% of controls while proglucagon mRNA signal density more than doubled. In insulinoma-bearing NEDH rats blood glucose averaged 34 ± 3.5 mg/dl; the proinsulin mRNA signal was virtually undetectable and proglucagon mRNA signal density was more than twice the controls. There was no detectable change in either β-cell area or islet number in rats subjected to fasting or insulin infusion, but in insulinoma-bearing rats β cell area was markedly reduced. Thus compensation during 4 d of starvation involves an increase in glucagon gene expression without change in insulin gene expression or β cell mass. In moderate insulin-induced hypoglycemia glucagon gene expression is increased and insulin gene expression decreased. In more profound insulinoma-induced hypoglycemia, in addition to the foregoing changes in hormone gene expression, there is a profound reduction in the number of insulin-expressing cells.

Original languageEnglish (US)
Pages (from-to)711-714
Number of pages4
JournalJournal of Clinical Investigation
Volume84
Issue number2
DOIs
StatePublished - Jan 1 1989

ASJC Scopus subject areas

  • Medicine(all)

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