Norepinephrine sensitivity of the endocrine pancreas in aging F344 rats

The effect of norepinephrine (NE) infusion on glucose-stimulated insulin secretion was evaluated in whole perfused pancreases isolated from 6-, 12-, and 26-month-old male Fischer 344 (F344) rats. Glucose-stimulated insulin secretion was significantly inhibited by NE in all age groups. There was no significant effect of aging on the sensitivity or magnitude of inhibition at any of the concentrations of NE. In contrast, vascular pressure attained during NE infusion was significantly less in the 26-month-old rats compared to 6- and 12-month-old animals. These results suggest that the adrenoceptor neuroeffector mechanism of the smooth muscle declines at a faster age-related rate than does the beta-cell's adrenoceptor mechanism.