Effect of prolonged fasting upon insulin and glucagon secretion from isolated rat pancreatic islets

To study insulin-glucagon interrelationships in the regulation of pancreatic islet functions, glucose-mediated insulin and glucagon secretion have been studied in isolated pancreatic islets from fed and from 4 and 8-day fasted rats. At low glucose levels (50 mg %) a continuous decrease of insulin and increase of glucagon secretion were observed during prolonged fasting. High glucose concentrations 300 mg %) stimulated insulin and inhibited glucagon secretion until 4 days, but did not cause any effect after 8 days fasting. These results suggest that the secretory mechanisms of the two hormones may have a common basis.