Effects of cytochalasin B and other agents on insulin secretion from saurian islets

Abstract

1. 1. The effects of Cytochalasin B, glucagon and theophylline, in the presence of a high concentration of glucose (5 mg/ml), on insulin release from pancreatic (splenic) islets of a lizard ( Anolis carolinensis) were studied in an in vitro perifusion system. 2. 2. Theophylline (10 −3 M) plus glucagon (1 μg/ml) effected a significant increase in insulin secretion, suggesting adenosine 3',5'-monophosphate modulation of insulin release from saurian pancreatic B cells. 3. 3. A biphasic pattern of insulin release, similar to that found with glucose alone, was observed with Cytochalasin B (5 μg/ml) included in the perifusion medium, but the amount of insulin secreted was significantly greater than with glucose alone. 4. 4. Cytochalasin B in the presence of theophylline plus glucagon resulted in a monophasic pattern and essentially linear rise in insulin release.