Interleukin-10 stimulates rat pancreatic islets in vitro, but fails to protect against interleukin-1.

Rat pancreatic islets were cultured for 42 h in medium supplemented without or with 0.1-10 ng/ml of human interleukin-10 (IL-10). Medium insulin accumulation was increased by 50% after culture with 0.1 ng/ml IL-10. All concentrations of IL-10 increased the islet insulin content, but did not affect the islet DNA content. IL-10 did neither affect basal and glucose-stimulated insulin secretion nor (pro)insulin and total protein biosynthesis rates. Addition of 25 U/ml of interleukin-1 beta during the last 24 h of culture, led to a marked inhibition of glucose-stimulated insulin release and a 5-6 fold increase in nitrite production by rat insulinoma cells. These events could not be counteracted by any concentration of IL-10. The present data suggest that IL-10 might in some aspects stimulate pancreatic beta-cell function, but it fails to block the inhibitory action of IL-1 beta.