Effect of atropine and vagotomy on pancreatic polypeptide response to a meal in dogs.

Abstract

In 4 conscious dogs the pancreatic polypeptide (PP) response to a standard beef-liver meal was measured by specific radioimmunoassay and compared with the response seen after the i.v. injection of 25 or 100 .mu.g/kg atropine. All 3 tests were performed twice in each animal and then repeated after truncal vagotomy. The mean prevagotomy postprandial PP increment was 85 .+-. 16 pmol/l in the first 2 h period and 54.5 .+-. 13 pmol/l in the 2nd. After the injection of 25 .mu.g/kg atropine there was significant reduction in the early response, but not the late. After 100 .mu.g/kg atropine sulfate, the response was significantly reduced during both periods. Truncal vagotomy significantly reduced the PP response over both time periods and the small residual response was completely abolished by atropine. In 5 additional dogs an infusion of bethanechol (100 .mu.g .cntdot. kg-1 h-1) caused a significant increase in the plasma concentration, which was abolished by pretreatment with atropine. PP release in response to a meal in the dog apparently is largely under vagal-cholinergic control.