Adenosine 3',5'-cyclic monophosphate and phosphodiesterase activities in isolated fetal and neonatal rat pancreatic islets.

Abstract

Adenosine 3',5'-monophosphate (cyclic AMP) and phosphodiesterase activity were assessed in isolated maternal fetal and neonatal rat pancreatic islets. Two- to three-fold increases in cyclic AMP content and phosphodiesterase activity were observed in neonatal islets from pups 24, 48 and 72 hr following spontaneous delivery with a decrease to normal adult levels by the 13th day postpartum. Cyclic AMP content and phosphodiesterase activity in isolated female adult islets were unchanged at all time periods examined both pre- and postpartum. Islets from 21-day-old fetal rats were not significantly different from maternal islets. Islets from nonfed neonates had smaller, but statistically significant, increases in cyclic AMP and phosphodiesterase activity. The relationship of these changes to fetal islet cell unresponsiveness to glucose and to the alterations in the insulin release mechanism which occur in the neonate is discussed. (Endocrinology 92: 614, 1973)