Effect of DI-n-pentyl phthalate treatment on testicular steroidogenic enzymes and cytochrome P-450 in the rat.

Treatment of young male rats with dipentyl phthalate (DPP) produced significant decreases in testicular cytochrome P-450, cytochrome P-450 dependent microsomal steroidogenic enzymes (17 alpha-hydroxylase, 17-20 lyase) and in the maximal binding of a natural substrate (progesterone) to testis microsomes. No effect was demonstrated by this compound on hepatic cytochrome P-450 content. Treatment of animals with a phthalate ester not causing testicular atrophy (diethyl phthalate; DEP) produced no significant changes in any of the parameters measured. This effect on the enzymes responsible for androgen production may be important as a mechanism of action involved in the development of phthalate-induced testicular damage.