Insulin‐like growth factor I reverses interleukin‐1β inhibition of insulin secretion, induction of nitric oxide synthase and cytokine‐mediated apoptosis in rat islets of Langerhans

Abstract

We have previously observed that treatment of rat islets of Langerhans with interleukin-1beta for 12 h results in nitric oxide-dependent inhibition of insulin secretion, while 48 h treatment increased rates of islet cell death by apoptosis. Here, we demonstrate that interleukin-1beta-mediated nitric oxide formation and inhibition of insulin secretion are significantly reduced by 24 h pretreatment of rat islets of Langerhans with insulin-like growth factor I (IGF-I). IGF-I decreased cytokine induction of nitric oxide synthase in islets. Use of an arginine analogue in culture or IGF-I pretreatment of islets were also effective in protecting islets against cytokine-mediated apoptotic cell death. We conclude that IGF-I antagonises inhibitory and cytotoxic effects of cytokines in rat islets.