Influence of imipramine and various steroids on hepatic in vitro N-demethylation of tricyclic antidepressants.

The effects of equimolar doses of imipramine (IP) and three catatoxic steroids, pregnenolone-16alpha-carbonitrile (PCN), spironolactone (SNL) and dexamethasone (DEXA), on hepatic mixed-function oxidases were investigated in female rats. Liver weight and N-demethylation of IP and amitriptyline (AMI) were significantly increased by 3 days of catatoxic steroid pretreatment. Repeated prior administration of IP enhanced N-demethylase activity and 9000g supernate protein, but diminished hepatic weight.