Metabolism of prostaglandin A1 by hepatic microsomal monooxygenase P-450 system in the guinea pig and rat.

This study demonstrates the metabolic transformation of prostaglandin A₁ (PGA₁) by guinea pig and rat liver microsomes. The transformation, which required NADPH and oxygen, yielded polar (presumably hydroxylated) products. Incubations with guinea pig liver microsomes yielded one zone of product on tlc, whereas rat liver microsomes produced two discernable metabolic zones. It was demonstrated that PGA₁ metabolism in the guinea pig and the rat was inhibited by the addition of SKF-525A, metyrapone, carbon monoxide and cytochrome $\text{C}$; nicotinamide (10 mM) inhibited only the guinea pig system. These findings indicate that the enzymatic activity responsible for PGA₁ metabolism is composed of a typical cytochrome P-450 monooxygenase system.