Human interleukin-1 beta induced stimulation of insulin release from rat pancreatic islets is accompanied by an increase in mitochondrial oxidative events.
Acute exposure of pancreatic islets to interleukin-1 beta results in an increase in insulin release, while an extension of the exposure time induces a functional suppression and eventually, destruction of the B-cells. We have recently suggested that the interleukin-1 beta induced inhibition of islet function is mediated through an impairment in oxidative metabolism. The aim of the current study was to investigate if the acute, stimulatory effects of interleukin-1 beta on islet function could also be related to changes in the substrate metabolism. For this purpose, rat islets were exposed for 90-120 min to 30 pmol/l human recombinant interleukin-1 beta (biological activity of 2.5 U/ml) and their function and metabolism characterized during this period. The cytokine did not increase insulin release in the presence of 1.7 or 5.5 mmol/l glucose but in both the presence of 16.7 mmol/l glucose or 10 mmol/l leucine + 2 mmol/l glutamine there was a 50% increase in insulin release. Interleukin-1 beta exposure increased the oxidation of D-[U-14C]glucose at 5.5 mmol/l glucose by 25% and at 16.7 mmol/l glucose by 60%. Carbohydrate and amino acid metabolism were further examined in the presence of D-[5-3H]glucose, D-[6-14C]glucose, [1-14C]pyruvate, L-[U-14C]glutamine, L-[U-14C]leucine and L-[1-14C]leucine. There was no difference between control islets and interleukin-1 beta exposed islets in terms of D-[5-3H]glucose utilization or [1-14C]pyruvate decarboxylation, but the oxidation of D-[6-14C]glucose was increased by 64% in the interleukin-1 beta exposed islets.(ABSTRACT TRUNCATED AT 250 WORDS)
Eizirik
D L
DL
Department of Medical Cell Biology, Uppsala University, Sweden.
Sandler
S
S
D000818:Animals; D002478:Cells, Cultured; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D005973:Glutamine / Q000378:metabolism; D006019:Glycolysis / Q000187:drug effects*; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007375:Interleukin-1 / Q000494:pharmacology*; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D007930:Leucine / Q000378:metabolism; D008297:Male; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D011773:Pyruvates / Q000378:metabolism; D019289:Pyruvic Acid; D051381:Rats; D011919:Rats, Inbred Strains; D011994:Recombinant Proteins / Q000494:pharmacology
D007328:Insulin; D007375:Interleukin-1; D011773:Pyruvates; D011994:Recombinant Proteins; D005973:Glutamine; D019289:Pyruvic Acid; D007930:Leucine; D005947:Glucose