Passage of I-131-albumin and I-125-gamma globulin into the small intestine of calves.

Intestinal transfer of I-albumin and I-gamma globulin was studied in 5 calves fitted with re-entrant intestinal loops. The passage of the two proteins across the intestinal wall proved highly variable (cf. Table II). However, the transfer of I-albumin and I-gamma globulin was of the same order of magnitude, which is taken as evideńce of similar transfer mechanisms of albumin and gamma globulin, in spite of different molecular weights. Instillations of hypertonic magnesium sulphate solution and of intestinal digesta were followed by increased transfer rates. It appears, therefore, that the passage of digesta will influence the transfer of proteins along the gut. It is emphasized that quantitation of the transfer as related to total catabolism of plasma proteins is subject to considerable inaccuracy.