Distribution and excretion of tritiated N4-behenoyl-1-β-D-Arabinofuranosylcytosine(BH-AC) in mice

Distribution and excretion of BH-AC[cytosine-5-3H] and BH-AC[behenoyl-14, 15-3H] in mice were studied and compared with that of Ara-C[cytosine-5-3H] by whole-body autoradiography and oxidation method. Ara-C[cytosine-5-3H] was equally distributed in each organ and rapidly excreted into the urine, while high radioactivity was detected in the liver, bile, blood, spleen, lungs, adrenals, bone marrow and a part of skin after i.v. administration of 3H-BH-AC. Ara-C[cytosine-5-3H] was not found in most of the organs 6 hr after the injection, but about 15 -- 20% and 5 -- 10% of the levels of radioactivity at 1 hr was detected in the liver and the other organs at 24 hr and 48 hr respectively after i.v. administration of BH-AC[cytosine-5-3H]. The distribution patterns of BH-AC[cytosine-5-3H] and BH-AC[behenoyl-14, 15-3H] were generally the same with two points of exception. First, a little radioactivity was seen in the thymus cortex, intestine and fetus after i.v. injection of BH-AC[cytosine-5-3H] where only a background level of radioactivity was seen after the administration of BH-AC[behenoyl-14, 15-3H]. Second, BH-AC[behenoyl-14, 15-3H] remained somewhat longer than BH-AC[cytosine-5-3H]. In the liver About 16 -- 20% and 60 -- 70% of BH-AC[cytosine-5-3H] was eliminated into the urine and feces within 6 hr and 24 hr respectively. More than 95% of the total radioactivity excreted was seen in the urine and less than 5% was found in the feces. (author)