Effect of gonadectomy on activity of neuronal 3β-hydroxysteroid dehydrogenase in some brain structures.

3β-Hydroxysteroid dehydrogenase is a key enzyme in the synthesis of steroid hormones in steroid-producing organs, including the brain producing neurosteroids. 3β-Hydroxysteroid dehydrogenase activity can be a marker of steroid-producing cells. We present the results of histochemical assay of this enzyme in the neocortex, hippocampus, and cerebellar cortex of gonadectomized prepubertal rats. The positive reaction was detected in hippocampal neurons, ganglionic layer cells of the cerebellar cortex (Purkinje cells), and solitary neocortical neurons of male and female rats. Gonadectomy significantly increased enzyme activity in neocortical (layer V) and hippocampal neurons and had no effect on the intensity of the reaction in Purkinje cells.