Effect of Sodium Nitroprusside on Amylase Secretion from Dispersed Rat Pancreatic Acini

Masahiko Ishimura*†, Yoshinori Kamisaki* and Tadao Itoh*

*Department of Clinical Phamacology and †First Department of Internal Medicine, Faculty of Medicine, Tottori University, Yonago 683, Japan

To clarify the direct action of nitric oxide (NO) on pancreatic exocrine, the effect of sodium nitroprusside (SNP), an NO donor, on pancreatic amylase secretion was investigated in the dispersed pancreatic acini of rats. Although SNP failed to stimulate the secretion of amylase, SNP (3 mmol/L) conbined with carbachol (3 µmol/L) or with CCK-8 (30 nmol/L) approximately doubled amylase secretion over that induced by either carbachol or CCK-8 alone. SNP also elevated the level of cyclic guanosine 3',5'-monophosphate (cGMP) to a much greater extent than either carbachol or CCK-8. Pretreatment of SNP elevated intracellular calcium ion concentration ([Ca²⁺]_i) both at rest and in the stimulated condition induced by carbachol or CCK-8. These findings suggest that SNP may promote the secretion of amylase stimulated by carbachol or CCK-8 through the elevation of cGMP and [Ca²⁺]_i.

Key words: amylase secretion; calcium;cGMP; nitric oxide; pancreatic acini

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