Localisation of the NADPH delta 4-3-keto steroid-5 alpha-oxidoreductase in the rat ovary.

The 5 alpha-reductase activity was localised on the stromal comportment of the rat ovary. The 5 alpha-reductase activity in stromal tissue decreased from 27.3 +/- 2.9 ng/hr/mg protein in rats 20 days old, to 13.4 +/- 1.2 ng/hr/mg protein in rats 30 days old and to 7.1 +/- 1.0 ng/hr/mg protein in adult rats. During the oestrous cycle no significant variations in enzyme activity could be demonstrated.