Effects of furosemide and indapamide upon pancreatic insulin and somatostatin secretion in vitro.

Antihypertensive treatment with furosemide and indapamide may eventually cause impairment of glucose metabolism. To study if this was due to a direct effect on the endocrine pancreas, we examined the effects of furosemide and indapamide on the release of insulin and somatostatin from the isolated perfused pancreas of normal dogs. Furosemide at concentrations ranging between 1-30 micrograms/ml inhibited insulin in a dose-dependent manner (2p less than 0.01) whereas the somatostatin secretion was left unchanged. Also the infusion of indapamide at doses ranging between 0.05-1 micrograms/ml subdued B-cell secretion at the two highest concentrations of 0.5 (by 15 +/- 2%, p less than 0.01) and 1 microgram/ml (by 22 +/- 5%, p less than 0.02) while pancreatic D-cell secretion did not alter. The results suggest, that furosemide and indapamide possess the ability to directly inhibit insulin secretion. Whether this effect is of clinical importance for the diminution in glucose tolerance observed during therapy remains, however, uncertain.