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Comparison of a new Tc-99m renal function agent, Tc-99m mercaptoacetyltriglycine, with I-131 OIH

Conference · · J. Nucl. Med.; (United States)
OSTI ID:5874751

The search for a Tc-99m replacement for I-131 hippurate (OIH) has led to the synthesis of (mercaptoacetyltriglycine) Tc-99m MAG/sub 3/, a N/sub 3/S derivative with a single stereochemical form, amenable to it formulation. Mouse biodistribution studies in control and probenecid treated animals indicated that renal excretion of Tc-99m MAG/sub 3/ was superior to OIH in both groups of animals. Protein binding studies, constant infusion clearance studies and extraction efficiencies were performed in rats to determine the potential of this agent for evaluation of renal function. In rat plasma TC-99m MAG/sub 3/ was 78% protein bound while OIH was 34% bound. The constant infusion clearance values for Tc-99m MAG/sub 3/ and OIH were 2.70 and 2.11 ml/min/ 100 gm body weight respectively. Clearance values were determined in the presence of IV administered competitive inhibitors, probenecid and para-aminohippuric acid (PAH). Extraction efficiency studies were performed in rats by arterio-venous differences for Tc-99m MAG/sub 3/ and OIH. Tc-99m MAG/sub 3/ was found to have an extraction efficiency of 84.8% while 69.4% was found for OIH. In summary, TC-99m MAG/sub 3/ is cleared more rapidly than OIH in normal rodents with high specificity. Its clearance, in the presence of tubular transport inhibitors, was similar to OIH when corrected for GFR.

Research Organization:
Univ. of Utah School of Medicine, Salt Lake City, UT
OSTI ID:
5874751
Report Number(s):
CONF-850611-
Journal Information:
J. Nucl. Med.; (United States), Journal Name: J. Nucl. Med.; (United States) Vol. 26:5; ISSN JNMEA
Country of Publication:
United States
Language:
English