Aging-associated pancreatic exocrine insufficiency in the unanesthetized rat

Observations in individuals have suggested that pancreatic functions may be diminished with aging. In order to explore this possibility, we measured pancreatic fluid, protein and amylase output as a function of aging in the rat. Surgical preparations of the rats included external drainage of pancreatic secretions without obstructing normal bile flow and complete diversion of gastric acid out of the duodenum to prevent endogenous secretin release. Pancreatic secretions were collected in the basal state in unanesthetized animals 24 h after surgery. Protein and amylase output were highest at 3 months of age and decreased to less than 20% of maximal values by 27 months of age. For example, amylase output decreased from 4,354 to 105 U/h/kg and protein output fell from 33.5 to 1.7 mg/h/kg between 3 and 27 months of age. Our findings indicate that aging in the rat is associated with diminished pancreatic exocrine functions. Further careful assessment of pancreatic functions in aging individuals is advisable.