Measurement Of Insulin-like Growth Factor Ⅱ In Serum And Follicular Fluid In Superovulation Cycle

It has been known that ovarian function is regulated by CNS-hypothalamus- pituitary-ovary axis. However, there are still some activities of ovary such as the selection and development of dominant follicles, the atresia of follicles and luteal functions that cannot be entirely explained by CNS-hypothalamus- pituitary-ovary axis. Researches have been focused on local organs such as ovary and endometrium recently. It has become obvious that cytokines produced within the ovary are important modulators of endocrine function and assist in the physiological processes by a local regulation of gonadotropin function and cell growth. The twin regulation by exogenous gonadotropins and endogenous cytokines has beenrecognized as the primary control of the ovarian cycle. However, it is not clear how these cytokines mediate the processes of oocyte maturation, steroidogenesis, follicle rupture and luteinization. Insulin-like growth factors system (IGF-I, II and their receptors, IGF binding protein 1-6 and their proteases) is one of the important regulatory systems in ovary. Evidence has indicated that IGF-II plays an important role in regulating the development of follicles and production of steroid hormones by ovary. But there are few articles that report the relationship between IGF-II and follicular development or production of steroid hormones in our country.It has been showed that human granulosa cells (GCs) cultured in vitro can synthesize and secrete IGF-II positively correlating with the numbers of the GCs. Conversely, IGF-II can stimulate human GCs proliferation in vitro and increase the release of progesterone (P) and estradiol (E₂) by the cultured human GCs in a dose-dependent pattern. It has been also showed that follicle-stimulating hormone (FSH) can stimulate the expression of IGF-II mRNA in human ovarian pre-antral follicles cultured in vitro. The result suggests that the mechanism of FSH promoting the follicular development and steroidogenisis may be partially via IGF-II /receptor pathway.It has been revealed that the IGFs are present throughout the maternal environment during early embryo development. Furthermore, the release of IGF-II was significantly greater than that observed for IGF-I. The IGF family plays an important role in enhancing embryo development. Thereforer, we hypothesized that the levels of IGF-II in human serum and follicular fluid (FF) may correlate with pregnancy rate.Ovarian hyperstimulation syndrome (OHSS) is a frequent serious complication in controlled ovarian hyperstimulation for in vitro fertilization and embryo transfer (IVF-ET). The pathogenesis of OHSS is still unclear. Early studies showed that E₂, P, prolactin (PRL), and prostaglandin (PG) might be involved in OHSS. Recent studies indicated that, in addition to E₂, P, PRL and PG, ovarian renin-angiotensin system (RAS), vascular endothelial growth factor (VEGF) and ovary inflammation factors (IL-1, 6, 8, TNF, et al) may also contribute to the pathogenesis of OHSS. According to the clinical observation, the genesis and progress of OHSS is usually related to ovarian hyperstimulation and the usage of human chorionic gonadotropin (hCG) for ovulation induction. For the intimate relationship between IGF-II and ovarian follicular development or secretion of steroid hormones by ovary, it was inferred that IGF-II might play a role in the pathogenesis of OHSS. Butuntil now, there has been lack of evidence showing the relationship between IGF-II and OHSS.In this study, we intend to analyze the expression patterns of IGF-II in serum and FF of patients undergoing gonadotropins stimulation for assisted reproductive techniques. Also we want to investigate the relationship between IGF-II levels in serum and FF and pregnant rate or OHSS.Material and methods SubjectsSerum and FF were obtained from 45 patients at the time of transvaginal oocyte retrieval after ovulation induction for in vitro fertilization (IVF) and embryo transfer (ET). The mean age of these patients was 30.93±3.54 years (range, 23⁴0 years).All patients underwent a standard leuteal...