Atropine suppression of basal and metoclopramide-induced human pancreatic polypeptide secretion in man.

The administration of metoclopramide (MET) increased human pancreatic polypeptide (hPP) levels in 17 of 18 male and female control subjects. In all the control subjects, the increase was from a mean (+/- SD) basal level of 96 +/- 60 pg/ml, to a peak of 221 +/- 170 pg/ml. The peak occurred at 30 min, and levels had decreased by 60 min in all subjects. Atropine pretreatment in five male control subjects significantly decreased basal hPP levels and completely abolished the response to MET. It thus likely that the hPP increase consequent to MET administration is related to the latter's cholinergic properties.