Inhibition of insulin secretion from rat islets of Langerhans by interleukin-6. An effect distinct from that of interleukin-1.
Glucose-induced insulin secretion from islets cultured in the presence of interleukin-6 (IL-6) for 12-24 h was inhibited to a similar extent as when islets were treated with interleukin-1 beta (IL-1 beta). However, unlike IL-1 beta, IL-6 did not potentiate insulin secretion during an acute (30 min) exposure of islets to the cytokine, nor did it inhibit DNA synthesis during a 24 h culture period. A 12 h pretreatment of islets with tumour necrosis factor-alpha (TNF-alpha) combined with IL-1 beta potentiated the inhibitory effect of IL-1 beta on secretion, such that 20 mM-glucose-induced insulin secretion was abolished. No synergistic inhibition of secretion was observed with TNF-alpha and IL-6. However, IL-1 beta and IL-6 were found to inhibit insulin secretion in an additive manner. These results suggest that IL-6 inhibits insulin secretion in a manner distinct from that of IL-1 beta, and that IL-6 is unlikely to mediate the inhibitory effects of IL-1 beta or TNF-alpha on rat islets of Langerhans.
Southern
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Department of Biochemistry, School of Biological Sciences, University of Sussex, Brighton, U.K.
Schulster
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D
Green
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IC
D000818:Animals; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D004261:DNA Replication / Q000187:drug effects; D005260:Female; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007375:Interleukin-1 / Q000494:pharmacology*; D015850:Interleukin-6 / Q000494:pharmacology*; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D051381:Rats; D011919:Rats, Inbred Strains; D011994:Recombinant Proteins / Q000494:pharmacology; D013936:Thymidine / Q000378:metabolism
D007328:Insulin; D007375:Interleukin-1; D015850:Interleukin-6; D011994:Recombinant Proteins; D004247:DNA; D013936:Thymidine