Abstract
The nitric oxide (NO) is assumed to be a modulator of the secretion of pancreatic hormones. Recently, it has been reported that a constitutive nitric oxide synthase (cNOS) located in all kinds of endocrine cells in the rat islets of Langerhans (Alm, et al., 1999). In the present study, we attempted to demonstrate the actual production of NO in the A- and B-cells of the islets of rat pancreas. Exocrine cells, islets, and other cells of the pancreas were dispersed by the collagenase method. The islets were picked up under a stereoscope and superfused with Krebs solution under the fluorescence microscope. After loading with 4,5-diaminofluorescein-2 diacetate (DAF-2 DA, 2.5 μM), a bright green fluorescence indicating production of NO was developed within a large number of islet cells. A- and B-cells of the islets were fixed and stained by immunohistochemistry for glucagon and insulin respectively. The stained islets were observed with confocal microscope (FV500, Olympus). The green fluorescence was observed in many insulin-immunoreactive B-cells. NO was also produced in glucagon-positive cells scattered in peripheral region of the islet. The results suggest that NO is continuously produced in A- and B-cells of the islet and modulates the secretions of glucagon and insulin. [Jpn J Physiol 54 Suppl:S218 (2004)]
