Noradrenergic Function in the Pancreatic Islets of Streptozotocin-Diabetic Aging Rats

Abstract

We studied age-related changes in the noradrenergic function in the pancreatic islets of streptozotocin diabetic male Wistar rats. Blood glucose, norepinephrine content, noradrenergic receptor binding, and cyclic adenosine monophosphate (cAMP) content were analyzed in the pancreatic islets of these rats. In the present study, the pancreatic islets of diabetic young and old rats showed a significant increase in noradrenaline content accompanied by a significant increase in Bmax and Kd for noradrenergic receptors compared with age-matched controls. The cAMP content increased significantly in diabetic young rats, whereas, in old rats a significant decrease was seen when compared with age-matched controls. These data demonstrate that the cAMP system is inhibited in the pancreatic islets of diabetic old rats, whereas it is stimulated in diabetic young rats. This might play a role in the early recovery shown by streptozotocin-treated young rats. Also, changes in the noradrenergic function in the pancreatic isle...