The induction of sister chromatid exchanges by cyclophosphamide in the presence of differently induced microsomal fractions of rat liver.
The induction of sister chromatid exchanges can be monitored by a test that incorporates the factor of metabolic activation in a simple manner. The results with cyclophosphamide show that in this test the induction of the metabolizing enzymes of the rat liver homogenates used is very important. 3-Methylcholanthrene induces little if any extra conversion of cyclophosphamide to SCE-inducing metabolites, compared with no induction. Aroclor 1254 and phenobarbital however, were very good inducers. The difference found between the liver homogenates concerning SCE induction corresponded with the differences in cyclophosphamide metabolism, which was measured as the decrease in NADPH induced by cyclophosphamide.
The induction of sister chromatid exchanges by cyclophosphamide in the presence of differently induced microsomal fractions of rat liver. The induction of sister chromatid exchanges can be monitored by a test that incorporates the factor of metabolic activation in a simple manner. The results with cyclophosphamide show that in this test the induction of the metabolizing enzymes of the rat liver homogenates used is very important. 3-Methylcholanthrene induces little if any extra conversion of cyclophosphamide to SCE-inducing metabolites, compared with no induction. Aroclor 1254 and phenobarbital however, were very good inducers. The difference found between the liver homogenates concerning SCE induction corresponded with the differences in cyclophosphamide metabolism, which was measured as the decrease in NADPH induced by cyclophosphamide.