Metabolism of daunomycin (NSC-82151) in vitro and the chemotherapeutic activity of isolated metabolites in vivo.

Daunomycin (D1) was quantitatively converted to a metabolite, D2 (> 98% conversion), by an aerobic, cell-free system containing nicotinamide adenine dinucleotide phosphate, reduced form (NADPH) and the 100,000 x g supernatant fluid of rat kidneys. Under lowered oxygen concentrations, cell homogenates plus NADPH converted D, quantitatively to an unknown metabolite, D(x), with D2 as a possible intermediate. The chromatographic properties of D(x) differed from those of D2 and the aglycones of D1 and D2 (D4 and D3 respectively).