Expression Of Steroidogenetic Enzymes During Developing Of Prepubertal Goat Ovarian Follicles

Folliculogenesis in mammalian ovaries is the first event towards the generation of offspring. The development and differentiation of follicles are closely associated with the ability of steroidogenesis, which depends on the expression and activity of steroidogenetic enzyme cytochrome P450 superfamily. Dozens of papers illustrated the expression of them for their individual experimental purpose, and the differences are found in different species. However there is no any systematic study about the expression of steroidogenetic enzymes in the goat. In this study, we determined the gene expression of cytochrome P450scc(P450 side chain cleavage), P450arom(cytochrome P450 aromatase) and P450c17(P450 17α-hydroxylase) mRNA during goat ovarian follicular development by RT-PCR and semiquantitative RT-PCR. Meanwhile, we compared the expression of the three genes between premature goat of 40-60 days old with adult goat. The homekeeping gene PO(acidic ribosomal phosphoprotein) is chosen for the endogenous reference gene for our semiquantitative RT-PCR.In conclusion, we find that: 1. the preantral follicles can't express P450arom mRNA, but express P450scc and P450c17 mRNA, which shows that the goat preantral follicles can't synthesize 17β-E2, but can synthesize prgnenolone and androstenedione; 2. 0.2-0.5mm antral follicles express P450arom mRNA , and the expression increases during the development of healthy antral follicles, which suggest that the follicles can already synthesized 17β-E2 as they reach 0.2-0.5mm diameter. 3. The oocytes can't synthesize any of the three enzymes; The theca cells can express P450scc and P450c17, but can't express P450arom; The basal granulosa cells and the cumulus cells can express both P450scc and P450arom mRNA, but can't express P450c17. 4. The atretic follices express P450scc and P450c17, but not express P450arom; Furthermore,the expression of P450scc remain at the same level as healthy antral follicles of the same diameter; The expression of P450c17 decreased compared with the healthy ones in the same size, and there...