EVALUATION OF THE BIODISTRIBUTION AND IN-VIVO BIOCHEMISTRY OF TC-99M-CYSTEINE AND TC-99 99M-CYSTEINE COMPLEXES - A POTENTIAL RENAL IMAGING AGENT/

Cysteine was chelated with (TC)-T-99m and/or Tc-99 in a freeze-dried k it containing Tin(II) ions, and the yellow Tc-99m/99-cysteine complex (complex I) was separated to study the biodistribution. Comparison of the distribution of Tc-99m/99-cysteine and Tc-99m-cysteine complexes w as made in rats and mice. The renal excretion patterns were studied in rats in the presence and absence of the renal tubular transport inhib itor 2,4-dinitrophenol. The carrier of Tc-cysteine complex in the bloo d and also the radioactive compounds in the urine were studied by HPGF C and SDS-electrophoresis, The kidney was confirmed as the target orga n; serum albumin serves as a carrier for transport of Tc-cysteine comp lex to the kidney. The Tc-cysteine complex was the primary form in exc reta, and glomerular filtration was the dominant excretory pathway.