Abstract
In vitro and in vivo studies on the absorption of TSP from rat intestine were carried out using 131I-labelled TSP. Sac of everted rat jejunum was placed in TSP containing Krebs-Ringer's bicarbonate buffer, and a significant quantity of caseinolytic activity was detected in the serosal fluid. 131I-TSP was administered in a loop of rat intestine, and the radioactivity was found in various organs including blood. 131I-bound substances in the blood serum, collected from the mesenteric vein, was analyzed by Sephadex gelfiltration, etc. Experimental results revealed the presence of 131I-bound protein in the serum of 131I-TSP received rats, whereas such 131I-protein was hardly found in the control 131I-KI received rat serum. Thus the possibility of the absorption of TSP through the intestine was also discussed.
