Neuronal NO synthase and its inhibitor PIN are present and influenced by glucose in the human beta-cell line CM and in rat INS-1 cells.

Nitric oxide (NO) is synthesised by different nitric oxide synthases (NOS) from L-arginine and acts as a signal transducer in a variety of cells. The neuronal isoenzyme of NOS (nNOS) was recently found in rodent beta-cells and beta-cell lines. We provide evidence that nNOS is also present in the human beta-cell line CM and that the specific inhibitor of nNOS PIN is expressed in CM and INS-1 cells. Furthermore, we investigated the influence of glucose on the activity of nNOS and the expression of PIN and are able to show that both are increased by glucose stimulation in the beta-cell lines but not in the mouse fibroblastic cell line LTK. This indicates that nNOS and PIN play a role in the specific function of beta-cells, not only in rodents but also in humans.