The distribution of 3H-aminoacetonitrile (AAN) and 3H-N (N-p-carboxyphenylglycyl) aminoacetonitrile (p-CPGAAN) in vivo was studied in rat tissues following intraperitoneal injections. The radioactivities of 3H-AAN and 3H-p-CPGAAN were most active in liver and kidney, and disappeared from all tissues in a similar manner. At 60 minutes after the administration of 3H-AAN or 3H-p-CPGAAN, radioactivities of both AAN and p-CPGAAN were recovered in subcellular fractions of rat liver in the following order: the supernatant fraction>the mitochondrial fraction>the microsomal fraction>the nuclear fraction. The distribution of 3H-p-CPGAAN in the particle fraction was less than 3H-AAN
Distribution of 35S-bis- (3, 5-dichloro-2-hydroxyphenyl) sulfoxide (35S-Bitin-S) in mice, rats and cockerels has been studied by means of whole body autoradiography and liquid scintillation counting. The radioactivity in male mice was marked in blood, liver, lung and connective tissues. The radioactivity in those tissues reached the highest level 6 hours after the administration, and thereafter decreased gradually. The radioactivity was not accumulated very much in the central nervous system, thymus, pancreas, spleen, brown fat, testis and endocrine glands. The 35S-Bitin-S or its metabolites passed the placental barrier and accumulated in certain tissues of the fetus. The concentration of radioactivity in fetal tissues was considerably lower than that in maternal tissues. The patterns of autoradiographic distribution of rats and cockerels were similar to those of mice. Approximately 70% of the administered dose of 35S-Bitin-S was absorbed from the ligated loop of rat's intestine in 4 hours. The concentration of 35S-Bitin-S in the tissues of rat after oral administration was the highest in plasma, relatively high in the liver and lung, and the lowest in the brain. It was found that the high concentration in the plasma lasted for a long time. The amount of 35S excreted in urine of rat in 6 day period after the administration was only 6 % of the administered radioactivity, whereas that in faeces in the same period was as high as 65 %