Nitric oxide production by the rat insulinoma cell line, RINm5F, Is specific for IL-1: a spectrophotometric IL-1 bioassay.

Cytokines inhibit glucose-induced insulin secretion from pancreatic beta-cells by stimulating the expression of nitric oxide synthase and the increased production of nitric oxide (NO). We have found that the rat insulinoma cell line, RINm5F, responds specifically and linearly to murine and human interleukin-1beta (IL-1beta) and IL-1alpha in the range of 0.1 to 1 unit/ml to produce nitric oxide. Other cytokines, including IL-2, IL-4, IL-6, IL-9, IL-11, IL-15, tumor necrosis factor-alpha, interferon-gamma, and lipopolysaccharide fail to stimulate nitric oxide formation by RINm5F cells either alone or in combination. In addition, these cytokines do not significantly potentiate or attenuate the IL-1 response. This unprecedented specificity to IL-1 has been further developed as a sensitive and specific assay for IL-1 bioactivity. Quantitation by this new bioassay of human IL-1beta and IL-1 released from activated murine peritoneal macrophages showed a close correlation with the quantitation of IL-1 by enzyme immunoassay (ELISA). This new bioassay, which is specific, nonradioactive and inexpensive, represents a significant improvement over current bioassays for IL-1.