Essentiality of circulating fatty acids for glucose-stimulated insulin secretion in the fasted rat

Daniel T. Stein, Victoria Esser, Brent E. Stevenson, Kirk E. Lane, James H. Whiteside, Murphy B. Daniels, Songyuan Chen, J. Denis McGarry

Research output: Contribution to journalArticlepeer-review

289 Scopus citations

Abstract

We asked whether the well known starvation-induced impairment of glucose- stimulated insulin secretion (GSIS) seen in isolated rat pancreas preparations also applies in vivo. Accordingly, fed and 18-24-h-fasted rats were subjected to an intravenous glucose challenge followed by a hyperglycemic clamp protocol, during which the plasma-insulin concentration was measured. Surprisingly, the acute (5 min) insulin response was equally robust in the two groups. However, after infusion of the antilipolytic agent, nicotinic acid, to ensure low levels of plasma FFA before the glucose load, GSIS was essentially ablated in fasted rats, but unaffected in fed animals. Maintenance of a high plasma FFA concentration by coadministration of Intralipid plus heparin to nicotinic acid-treated rats (fed or fasted), or further elevation of the endogenous FFA level in nonnicotinic acid-treated fasted animals by infusion of etomoxir (to block hepatic fatty acid oxidation), resulted in supranormal GSIS. The in vivo findings were reproduced in studies with the perfused pancreas from fed and fasted rats in which GSIS was examined in the absence and presence of palmitate. The results establish that in the rat, the high circulating concentration of FFA that accompanies food deprivation is a sine qua non for efficient GSIS when a fast is terminated. They also serve to underscore the powerful interaction between glucose and fatty acids in normal β cell function and raise the possibility that imbalances between the two fuels in vivo could have pathological consequences.

Original languageEnglish (US)
Pages (from-to)2728-2735
Number of pages8
JournalJournal of Clinical Investigation
Volume97
Issue number12
DOIs
StatePublished - Jun 15 1996

Keywords

  • antilipolysis
  • fatty acids
  • insulin secretion
  • nicotinic acid
  • stimulus-secretion coupling

ASJC Scopus subject areas

  • Medicine(all)

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