Progesterone synthesis by luteal mitochondria in vitro.

Mitochondria were prepared from bovine corpora lutea by differential centrifugation and were purified by isopycnic zonal centrifugation. A marked increase in specific cytochrome oxidase activity and a marked decrease in specific DNA and RNA content indicate that the procedure resulted in a highly purified preparation of mitochondria. These organelles had a higher rate of conversion of [4-14C] cholesterol to [4-14C] progesterone than did mitochondria separated only by differential centrifugation, suggesting that luteal mitochondria contain the enzyme systems required for progesterone synthesis.