Abstract
To investigate the intestinal absorption of parotin, 125I-labelled parotin was added in the mucosal side of the sac of rat everted intestine and incubated for 1 hr. Parotin seemed to be transmitted through the intestinal wall into the serosal fluid, because the non-diffusible 125I-bound substance which reacted with the anti-parotin rabbit serum was detected in the serosal fluid. The amount of 125I-macromolecule in the serosal fluid which was estimated from the radioactivity was in good agreement with that of the immunoreactive substance in the fluid determined by a single radial immunodiffusion, and the concentrations of these substances in the serosal fluid were about 1/5 of parotin concentration in the mucosal fluid.
Apart from this, in situ mesenteric perfusion was performed on the rats which were administered parotin and 125I-labelled parotin in the ligated jejunum. The perfusate was collected from the mesenteric vein for 2 hr, and 125I-bound macromolecule which corresponded to 3.4% of the administered 125I-labelled parotin was found in the perfusate. There was an immunoreactive substance with the anti-parotin serum in the perfusate, too.
From these results, it was inferred that about 3% of parotin given into the intestine was transmitted into the mesenteric blood vessels.
