Acinar cell responsiveness to urecholine in the rat pancreas during fetal and early postnatal growth.

These studies were performed to determine when, during fetal or postnatal life, rat pancreatic acinar cells acquire their capacity to respond to cholinergic drugs. The release of amylase, lipase, and chymotrypsin from rat pancreas in response to urecholine was measured in vitro. Fetal and newborn pancreas did not respond to 10(-5) M urecholine; 3-day- to 15-day-old pancreas demonstrated an increasing response to this dose. Peak sensitivity when compared to adult pancreas was present between days 15 and 21. Our results indicate that the exocrine pancreas acquired a responsiveness to urecholine on the 3rd day of postnatal life and becomes more sensitive to stimulation from the 15th day.