Hisao Sone

Tissue distribution of radioiodinated Ricinus lectins

Abstract Two Ricinus lectins, ricin D and castor bean hemagglutinin (CBH) were iodinated with different numbers of diiodotyrosine (DIT) per molecule and trace labeled with iodine-125. The distribution in rat tissues after intraperitoneal and intravenous injection was investigated as a function of the degree of iodination of the lectins. A high specific affinity to the pancreas was found after intraperitoneal injection. About 6% of the administered dose/gram was localized in the pancreas at 30 min after injection of 3 DIT, 125 I-CBH and the pancreas to liver ratio was 16:1 (% dose/g). In the case of ricin D, the uptake in the pancreas was about 3% dose/g, at 30 min after injection of 3.6 DIT, 125 I-ricin D and the pancreas to liver ratio was 12:1 (% dose/g). No uptake, except in the liver, was observed after intravenous injection.

On Renal Excretion of Sodium 4-iodo-5-methylpyrazole-3-carboxylate-131I

Sodium 4-iodo-5-methylpyrazole-3-carboxylate-131I(IMPC-131I) was synthesized by isotope exchange with Na 131I in the molten state to evaluate its potential usefulness as a renal function and/or imaging agent. Tissue distribution and clearance characteristics of IMPC-131I are described. Tissue distribution experiments in rats indicated a very high renal concentration of radioactivity following intravenous administration. At 5 min the kidney took up 27.8% of the injected dose (16.1% dose per gram) and the total activity in the kidney still accounted for 9.8% of the injected dose at 30 min, with only 1.2% localizing in the liver. The ratios for kidney-to-liver in the concentration of IMPC-131I were always higher than those of hippuran -131I throughout the period of the experiment. Within 24 hr, 78.6% of the injected dose were excreted in the urine. The autoradiographic and the scannographic studies were also performed. The present results suggest that IMPC-131I has potential as a new agent for both funciton and imaging studies of the kidney.