ABOMASAL INTERSTITIAL FLUID-TO-BLOOD CONCENTRATION GRADIENT OF PEPSINOGEN IN CALVES WITH TYPE-1 AND TYPE-2 OSTERTAGIOSIS

Pepsinogen and protein concentrations were determined in blood samples , collected from the left gastroepiploic artery and vein, and in aboma sal lymph from 15 steers naturally infected with Ostertagia ostertagi and 4 uninfected steers. In steers with type-1 ostertagiosis, the conc entration gradient between the mucosal interstitium and the blood alon e could account for higher than normal serum pepsinogen concentrations . High interstitial pepsinogen concentrations may have resulted from i ncreased epithelial permeability or increased pepsinogen production an d secretion. However, in steers with type-2 ostertagiosis, the concent ration gradient could not entirely account for the high serum pepsinog en concentrations, suggesting that capillary permeability or surface a rea may have been altered. Lymphatic uptake contributed pepsinogen to the blood in all infected steers.