title: The absorption, distribution, metabolism, and excretion of 125I-labeled sfericase in rats.
abstract: 125I-sfericase was given orally, intravenously, or intraduodenally to rats. In vivo behavior of radioactivity was investigated to determine absorption, distribution, metabolism, and excretion of sfericase. Moreover, the effects of TCA treatment and dialysis on the ratio of radioactivities in high molecular fractions were also studied. Following oral administration (about 10 microCi/rat), the blood radioactivity level peaked at 1-2 h and then rapidly decreased. The cumulative percentages of radioactivities in lymphatic fluid, urine, and feces within the first 24 h were 5.85%, 9.17%, and 2.56% (mean), respectively. Relatively high organ tissue levels of radioactivity were recorded for the thyroid gland, stomach, cecum, kidney, blood, and lung at 2 h, but in all except the thyroid gland a remarkable decrease in radioactivity was observed at 24 h after administration. Totals of 0.66%, 1.91%, 0.869%, and 2.36% (mean), respectively, of the radioactivity found in whole plasma and homogenates of liver, kidney, and spleen were transferred into the TCA precipitable fraction. These rates of transference were lower than those observed after iv administration (about 5 microCi/rat).
mesh_terms: D000042:Absorption; D000818:Animals; D010450:Endopeptidases / Q000378:metabolism*; D007457:Iodine Radioisotopes; D008196:Lymph / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012697:Serine Endopeptidases; D014018:Tissue Distribution
chemical_list: D007457:Iodine Radioisotopes; D010450:Endopeptidases; D012697:Serine Endopeptidases; C038978:sfericase