| Cystic follicles develop when one or more follicles fail to ovulate and subsequently do not regress but maintain growth and steroidogenesis. Cystic follicles are one of the most common causes of reproductive failure in pig. This condition can result in significant economic losses to the pig industry.Many reasons are responsible for the ovarian follicular cysts. Normolly, ovarian cycle is regulated by axis of hypothalamus-pituitary -ovaries with other cell factors, which ensure the endocrine balance and normal reproductive actions in animals. Disorder of any part in axis will result in ovarian follicular cysts. More and more researchs prove that the disorder of endocrine system is a major reason to the ovarian follicular cysts.Follicle stimulating hormone (FSH) and luteinizing hormone (LH) are biosynthetized and secreted by prehypophysial gonadotroph. Both of them are called gonadotrophic hormone (GTH). There have been many researches on the regulatory mechanism of the GTH secretion anterior receptors. FSH and LH play their roles by binding their specific receptor (FSHR and LH/CGR). The quantityand activeness of FSHR and LH/CGR which are expressed on the Graafian follicle not only restrict the functions of FSH and the LH, but adjust the secretions of FSH and LH as well. Therefore, the post- receptor mechanism regulating the synthesis and secretion of gonadotrophins is one of main research areas at present .Endomembrane cells of antral follicles secret kinds of enzymes, for example cytochrome P450, side chain cleavage enzyme, cytochrome P450 17α-hydroxylation, and 3β-hydroxysteroid dehydrogenase (3β- HSD), of which 3β- HSD is an important enzyme to synthesize the steroid hormones.There are no reports about the expression of FSHR and 3β-HSD in the different antral follicles and ovarian follicular cysts. Although there are some reports about the expression of LH/CGR in the different antral follicles and ovarian follicular cysts, further work still need to be done.In order to the mechanism of gonadotrophins and steroidogenic enzyme in the development of follicle and ovarian follicular cysts, we have studied the expression of FSHR, LH/CGR, and 3β-HSD in the antral follicles and ovarian follicular cysts in the present study. The expression levels of the FSHR, LH/CGR, and 3β-HSD in antral follicles and ovarian follicular cysts.were detected by RealTime-PCR.The results showed that the expression levels of FSHR in group of 3-5mm and 5-8mm were higher than that in group of 8-10mm. The expression level of LH/CGR and 3β-HSD in group of 8-10mm was higher than those in group of 3-5mm and 5-8mm. The expression levels of FSHR, LH/CGR and 3β-HSD in ovarian follicular cysts were higher than that in group of 8-10mm, with a significant difference in FSHR mRNA, and highly significant differences in LH/CGR and 3β-HSD mRNAs (p<0.05).In conclusion, the present study has investigated the mRNA expression levels of FSHR, LH/CGR, and 3β-HSD, and discussed the mechanisms of action of FSHR, LH/CGR, and 3β-HSD in the normal follicles at different stages of development and ovarian follicular cysts. According to the results, we presume that high mRNA expression levels of the FSHR, LH/CGR, and 3β-HSD may be associated with strengthening of action of gonadotropins, prolongation of growth of the dominant follicle and secretion of more estrogen, which result in the ovarian follicular cysts. The present study provides f urther molecular basis for the etiopathogenesis of the ovarian follicular cysts.
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