Influence of Physical and Chemical Treatments upon the Microsomal Enzymes of Testes related to Androgen Biosynthesis

Abstract

Testicular microsomal fraction (10, 000-105, 000 x g precipitates) of adult rats which was responsible for enzymic transformation of pregnenolone into testosterone was inactivated by phospholipases C and D, but not by phospholipase A. After the 10 kilocycles/sec. sonication for 60mins., most of the microsomal enzyme activities were still found in the 105, 000 x g precipitates. The specific activities of the enzymes in the precipitates at 105, 000 x g became higher than those of the untreated microsomal particles, as inactive protein was solubilized from the microsomal fraction by this sonication. After the 20 kilocycles/sec. sonication for 5 mins., however, appreciable activities of the testicular enzymes related to testosterone formation were found in the supernatant fluid at 105, 000 x g, but were mostly precipitated at 165, 000 x g for 5hrs., indicating that the sonication modified the microsomal structure of testis without serious loss of the enzyme activities related to the androgen biosynthesis. Influences of the phospholipases A and C upon the 20 kilocycles/sec. sonicated microsomal fraction of testes were similar to those of the same enzymes upon the intact microsomes. By treatments of it with organic solvents, surface active reagents, and freezing and thawing procedure, the microsomal enzymes could not be solubilized with retention of the enzyme activities.From the results obtained by the above physical and chemical treatments against testicular microsomal fraction, the status of the testicular enzymes in the microsomal structure was discussed.