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

Summary: Destroying beta-cells in the pancreas has mostly the same effects in young and old rats, but not exactly the same.

Interestingness: 1

Paper by Asha Abraham and Cheramadathikudyil S Paulose in the Journal of Anti-Aging Medicine, Volume 2, Issue 1, Spring 1999.

(((This is the first of most likely most of papers in which I give up even attempting a half-assed summary)))

(((After chemically destroying the beta cells in the pancreas of young and old rats and thus making them "diabetic", they measured higher glucose concentrations, higher noradrenaline receptors, higher noradrenaline concentration in the pancreas and higher binding constants of noradrenaline receptors in both young and old diabetic rats. cAMP concentration went way up in the young and a bit down in the old. This might mean something. Their guess is alpha2-adrenergic receptors get more sensitive during old age, beta-adrenergic in young rats. Alpha2-adrenergic receptors inhibit insulin release. Beta-adrenergic increase cAMP)))


Abstract follows:

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 islets occurring during aging might account for the increased risk of diabetes mellitus with age.