Metabolic adaption of pancreatic islet tissue in aging rats.

A previous report indicating reduced glucose metabolism in pancreatic islets isolated from old as compared with young rats was reinvestigated. With a modified islet isolation procedure it was found that islets from 12- to 18-month-old rats had increased glucose use, elevated glucokinase, phosphofructokinase and glucose-6-phosphate dehydrogenase when compared with islets from 2-month-old controls. Glucose-induced insulin release in vitro of islets from the older rats was also improved by the more careful method of islet isolation but did not achieve rates observed with islets from young rats. The data suggest an age-related activation of pancreatic islet cell metabolism, possibly in response to overstimulation by increased peripheral insulin resistance, characteristic of older obese rats.