Cholesterol ester hydrolysis by homogenates of whole testis, seminiferous tubules and interstitial cells of mature rats.

The characteristics and localization of a cholesterol ester hydrolase enzyme in homogenates of whole testis and in isolated seminiferous tubules and interstitial cells of mature rats have been investigated. Hydrolysis of cholesteryl [1(-14)C]oleate occurred at an optimum pH of 7.0, was linearly related to time up to 5--6 h of incubation and increased linearly up to 0.25 mg protein/incubation. Hydrolytic activity was inhibited by increasing the incubation temperature from 29 to 41 degrees C and by sonication. Cholesterol ester hydrolase activity/mg protein was three times greater in homogenates of seminiferous tubules than in interstitial cells. Cholesterol ester hydrolase may function to provide precursors for use in seminiferous tubular steroid hormone biosynthesis or germ cell maturation.