The ingestion of dietary protein as large molecular mass degradation products in adult rats

Proteins fed orally to adult rats are transported into the circulation in the form of break down products of large molecular mass (b. d. p.). As much as 40% of the fed dose, in the case of bovine IgG, is present in the carcase as tungstic precipitable material after so feeding. Ferritin and α-gliadin are treated similarly. Preliminary oral immunization with bovine IgG leads to a reduction of this passage if a test dose is given later, but much is still transported. This is in agreement with the expectation that rats which have been fed a normal cereal containing diet should be immune to α-gliadin, yet still show transport of this molecule or its b. d. p. The implications of this finding for the physiology and immunology of ingestion are discussed.