The role of phospholipids in the activity of delta4-3-ketosteroid 5alpha-oxidoreductase of the rat ventral prostate.

The involvement of phospholipids in the activity of 5alpha-reductase from nuclear and microsomal fractions of rat prostate was studied using phospholipases A and C. Phospholipase A reduced the activity of 5alpha-reductase in both subcellular fractions; this effect was not attributable to the hydrolysis products. Phospholipase C stopped only the activity of the nuclear fraction. There was no quantitative correlation between hydrolysis of phospholipids and loss of enzyme activity. The inactivation observed seems to result from phospholipase-induced instability of the enzyme. The results suggest that the altered structure of phospholipids and/or the membranes where 5alpha-reductase is located is responsible for the decrease in activity.