Abstract: 50

NO EXPRESSION OF STEROIDOGENIC ACUTE REGULATORY PROTEIN IS DETECTED IN THE FOLLICLES OF PREGNANT RAT OVARY.

Yi-Jun Chen¹ , Qiang Feng^{1 *}, Hong-Juan Gao¹ , Yi-Xun Liu^{1 *}
State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences ¹

The steroidogenic acute regulatory protein (StAR) is believed to be the key regulator of steroid hormone biosynthesis. The StAR is required for the intramitochondrial translocation of cholesterol to the cholesterol sidechain cleavage complex, which is located on the matrix side of the inner mitochondrial membrane, and this is the rate-limiting step of the steroidogenesis. It is proved that StAR expresses in all tissues that are capable of steroidogenesis and only those tissues synthesizing steroid hormone express StAR. Therefore the expression of StAR is necessary for the cells to synthesize steroid hormone. Antral follicles are present in the ovaries throughout gestation. These follicles are physically immature and can not ovulate under the induction of LH/hCG. The purpose of the present study is to examine whether follicles in pregnant rat ovaries are capable of steroidogenesis. We used antisense StAR probe and anti-StAR rabbit serum to detect the StAR expression in various stages of pregnant rat ovary follicles. The results indicated that theca-interstitial cells and the membrane granulosa cells at the stages from the estrous or pre-estrous in the normal cycling rat ovary express StAR mRNA and protein, whereas neither granulosa cells nor the theca cells in pregnant ovary throughout gestation express StAR. The results indicate that the follicles throughout the gestation are incapable of steroidogenesis.

    This abstract is being presented on Sunday, August 1 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.