Interleukin‐1 inhibits glucose‐induced Ca2+ uptake by islets of Langerhans

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Abstract
Recombinant interleukin‐1 (rIL‐1) is known to inhibit glucose‐induced insulin secretion by islets of Langerhans, a novel target tissue of cytokine. We have investigated whether rIL‐1 pretreatment affects biochemical mechanisms known to be involved in the regulation of Ca2+ homeostasis during glucose‐induced insulin secretion. Glucose‐induced Ca2+ uptake by intact islets through the plasma membrane was dramatically inhibited (96%) by rIL‐1 (2 nM). rIL‐1, however, did not affect Ca2+ uptake by, or Ins 1,4,5‐P3‐induced Ca2+ efflux from, the endoplasmic reticulum in digitonin‐permeabilized islets, although glucose‐induced accumulation of inositol trisphosphates was inhibited (38%). These results suggest that perturbation of intracellular Ca2+ homeostasis in islets is involved in inhibition of insulin secretion by rIL‐1.