Aging impairs pancreatic response to refeeding following a protein-free diet

Changes in content and recovery of pancreatic enzymes after a protein-free diet were examined in young (8-month) and old (26-month) Fischer-344 female rats. In control rats fed a normal diet for 15 days, no significant difference between young and old rats was observed in pancreatic weight or in pancreatic content of protein, enzymes, and DNA. A 7-day protein-free diet significantly decreased pancreatic wet weight as well as content of protein, chymotrypsin, amylase, and DNA in both age groups, whereas body weight and amount of daily food intake did not differ from respective control values (in normal diet-fed rats) in either age group. In young rats, chymotrypsin and protein contents were significantly greater than control values during the recovery period in which rats were fed a normal diet following the 7-day protein-free treatment. In contrast, these values in old rats remained lower than corresponding control values throughout the entire recovery period. These results agree with our previous study suggesting that aging probably attenuates the reserve capacity of the pancreas for enzyme secretion, but not its basal functions.