Effect of an antimuscarinic drug on the plasma pepsinogen activity of sheep infected with Ostertagia circumcincta

The antimuscarinic drug atropine caused a marked fall in plasma pepsinogen values of sheep with burdens of Ostertagia circumcincta and this response was greater in animals which had higher plasma pepsinogen values before administration of the drug. The response was shown to occur whether the elevated plasma pepsinogen values were a consequence of a larval infection in previously naive or exposed animals or of adult parasites directly transplanted into the abomasum of naive lambs.