Effects of heme oxygenase isozymes on Leydig cells steroidogenesis.

In the present study, we demonstrate the expression of heme oxygenase (HO) isozymes, HO-1 and HO-2 (listed as HMOX1 and HMOX2 in the MGI Database), in MA-10 Leydig tumor cells and its effect on steroidogenesis. The well-known HO inducer, hemin, increased both HO-1 and HO-2 protein levels and HO-specific activity. Induction of HO by hemin inhibited basal, hCG-, and dibutyryl cAMP (db-cAMP)-induced steroidogenesis in a reversible way.