Abstract: Aim The effects of nicotinamide (NA) on interleukin-ip-induced destruction of isolated rat pancreatic islets of Langerhans were observed. Method Isolated pancreatic islet cells from SD rat were cultured in monolayer in vitro. Nitrite production, insulin release, islet cell DNA and insulin content, and cell activity (MTT assay) in rat pancreatic islet cells incubated with IL-1β or/and NA (10,20 mmol/L),were measured. Results IL-lβinduced a significant increase in nitrite production, inhibited the medium insulin accumulation and the glucose-stimulated insulin, release, and decreased islet cell DNA insulin content and MTT(P<0.001).The inhibitory activities were blocked by NA in a higher dose (20 mmol/L) (P<0.001) while in a lover dose. NA (10 mmol/L) prevented the IL-lβ-induced cytotoxic effects without affecting nitrite production and the glucose-stimulated insulin release. Conclusion IL-lβ-induced nitric oxide (NO) production alone is insufficient to account for the IL-lβ-mediated islet p-cell destruction. Mechanisms of other action of the IL-1β may be involved. There may be a variety of mechanisms the protective effects of NA against cytotoxic action of IL-1β, including inhibition of NO Production, which may be related to exposure concentration of NA.

Key words: nicotinamide, interleukin-1, nitric oxide, islets of Langerhans