Starvation-induced Changes of Palmitate Metabolism and Insulin Secretion in Isolated Rat Islets Stimulated by Glucose

Biochem J. 1984 Jul 15;221(2):317-24. doi: 10.1042/bj2210317.

Abstract

The influence of 48 h starvation on glucose-induced changes of palmitate metabolism and insulin release in isolated rat islets was investigated. (1) Islet insulin response to 20 mM-glucose was abolished after 48 h starvation, and it was restored by 0.25 mM-2-bromostearate, an inhibitor of fatty acid oxidation. (2) The increase in glucose concentration from 3 to 20 mM was accompanied by a 50% decrease in the oxidation rate of 0.5 mM-[U-14C]palmitate in control (fed) islets, and a concomitant increase (100%) in its incorporation into triacylglycerol and phospholipid fractions. (3) Starvation induced a higher basal (3 mM-glucose) rate of palmitate oxidation, which was resistant to inhibition by 20 mM-glucose. The latter also failed to increase palmitate incorporation into islet triacylglycerols and phospholipids. (4) 2-Bromostearate (0.25 mM) strongly inhibited the high oxidation rate of palmitate in islets of starved rats, and allowed a normal stimulation of its incorporation rate into islet lipids by 20mM-glucose. (5) The results suggest that starvation restricts islet esterification of fatty acids by inducing a higher rate of their oxidative degradation that is insensitive to regulation by glucose.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Glucose / metabolism
  • Glucose / pharmacology*
  • In Vitro Techniques
  • Insulin / metabolism*
  • Islets of Langerhans / drug effects
  • Islets of Langerhans / metabolism*
  • Oxidation-Reduction
  • Palmitic Acid
  • Palmitic Acids / metabolism*
  • Perfusion
  • Phospholipids / metabolism
  • Rats
  • Rats, Inbred Strains
  • Starvation / metabolism*
  • Stearic Acids / pharmacology
  • Triglycerides / metabolism

Substances

  • Insulin
  • Palmitic Acids
  • Phospholipids
  • Stearic Acids
  • Triglycerides
  • 2-bromostearic acid
  • Palmitic Acid
  • Glucose