SKF 525-A inhibition of hepatic monooxygenase activity in rhesus monkeys.

Pretreatment of 3 male rhesus monkeys (Macaca mulatta) with SKF 525-A(20 mg/kg, i.m.) 3 h prior to to injecting 14CH3-N-antipyrine (30 mg/kg, i.v.) increased antipyrine plasma half-life (APH) 240--500%; measurements of APH made 4, 8 and 11 days after SKF 525-A treatment were also higher than control values. Increases correspond to decreased plasma levels of 3-hydroxymethylantipyrine and 4-hydroxyantipyrine and decreased rates of aldrin epoxidation in liver biopsy homogenates. Comparison of HSLC and radiometric methods for determining APH showed that both methods were capable of detecting chemically altered hepatic monooxygenase activity.