Effect of cadmium on pulmonary and renal microsomal drug metabolizing enzymes of the guinea-pig

Abstract

1. 1. The effect of acute cadmium (Cd) treatment on pulmonary and renal microsomal aniline 4-hydroxylase and ethylmorphine N-demethylase enzyme activities of adult male guinea-pigs were assessed 72 hr following a single dose of Cd ion (2mg Cd 2+/kg i.p.). Tissue and microsomal Cd levels were also determined. 2. 2. There were no significant differences between either lung or kidney tissue weights, microsomal protein contents or enzyme activities of Cd treated and control animals. 3. 3. The tissues and microsomes of Cd-treated animals were found to have significantly higher levels of Cd than those of control animals. In Cd treated animals, tissue and microsomal Cd levels of kidney were found to be higher than that of lung. 4. 4. In vitro addition of cadmium chloride (CdCl 2) to incubation mixtures produced concentration related inhibitions of microsomal drug metabolizing enzymes in each tissue. However, in vitro effect of CdCl 2 was found to be stronger on drug metabolizing enzymes of kidney than those of lung. In addition, while the strength of Cd effect was more pronounced on the activity of ethylmorphine N-demethylase than that of aniline 4-hydroxylase in the lung, the opposite was observed in the kidney.