Synthesis of mitochondrial proteins after stimulation of ovarian follicles by luteinizing hormone.

Treatment of isolated ovarian follicles with LH results in an increase in pregnenolone and progesterone secretion. Furthermore, LH treatment of follicles increases mitochondrial cholesterol conversion activity but does not significantly affect the mitochondrial ATP synthesis rate. Since these changes in pregnenolone synthesis may be due, at least in part, to changes in the components of mitochondria, we investigated the synthesis of mitochondrial proteins in response to treatment of follicles with LH. Follicles (4–6 mm in diameter) were isolated from porcine ovaries and incubated for 24 h without or with LH (1<μg/ml medium 199D), in the presence of [3H]leucine (without LH) or [14C]leucine (with LH). Untreated and LH-treated follicles were combined, and a mitochondrial sample was prepared. The mitochondrial proteins were separated by sodium dodecyl sulfate-gel electrophoresis using 8% and 15% polyacrylamide gels, and the 14C to 3H ratio of slices was determined. General incorporation of radiolabeled leucin...