Early hCG addition to rFSH for ovarian stimulation in IVF provides better results and the cDNA copies of the hCG receptor may be an indicator of successful stimulation

A simple, safe and cost-effective treatment protocol in ovarian stimulation is of great importance in IVF practice, especially in the case of previous unsuccessful attempts. hCG has been used as a substitute of LH because of the degree of homology between the two hormones. The main aim of this prospective randomized study was to determine, for the first time, whether low dose hCG added to rFSH for ovarian stimulation could produce better results compared to the addition of rLH in women entering IVF-ET, especially in those women that had previous IVF failures. An additional aim was to find an indicator that would allow us to follow-up ovarian stimulation and, possibly, modify it in order to achieve a better IVF outcome; and that indicator may be the cDNA copies of the LH/hCG receptor. Group A patients (n = 58) were administered hCG and Group B rLH (n = 56) in addition to rFSH in the first days of ovarian stimulation. The number of follicles and oocytes and, most importantly, implantation and pregnancy rates were shown to be statistically significantly higher in the hCG group. This study has also determined, for the first time to our best knowledge, m-RNA for LH/hCG receptors in the lymphocytes of peripheral blood 40 h before ovum pick-up. cDNA levels of the hCG receptor after ovarian stimulation were significantly higher among women receiving hCG compared to those receiving LH. In addition, higher levels were encountered among women with pregnancy compared to those without, although this was not statistically significant due to the small number of pregnancies. It seems that hCG permits a highly effective and more stable occupancy of rLH/hCG receptors and gives more follicles and more oocytes. The determination of cDNA copies could be, in the future, a marker during ovulation induction protocols and of course a predictor for the outcome of ART in the special subgroup of patients with previous failures

Update on the role of ovarian corticotropin-releasing hormone

Corticotropin-releasing hormone (CRH) is a 41-amino acid peptide synthesized by neurons of the parvocellular and paraventricular hypothalamic nuclei. Central CRH is the principal regulator of the stress system influencing several systems in the brain and influenced by them. It activates the secretion of glucocorticoids and indirectly regulates the immune system and the immune response. Peripheral CRH is secreted by postganglionic sympathetic and unmyelinated sensory afferent neurons and has been identified in several peripheral tissues and organs, including those of the reproductive system (ovary, endometrium, placenta, and testis). In the human ovary, receptors are detected in thecal and stromal cells and in follicular fluid. Ovarian CRH regulates ovarian steroidogenesis and is involved in follicular maturation, ovulation, and luteolysis. In this concise review we briefly discuss the role of ovarian CRH in reproduction, emphasizing its role in oocyte maturation. © 2010 New York Academy of Sciences

Oocyte maturation in assisted reproductive techniques

Human oocyte maturation is a long process during which nuclear maturation occurs resulting in germinal vesicle breakdown (transition from prophase I to metaphase II) and extrusion of the first polar body. During oocyte maturation, in parallel with nuclear maturation, a number of events take place in the oocyte cytoplasm that assist fertilization and early embryonic development. So far several attempts have been made to mature human oocytes in vitro. The main patient group to which in vitro maturation (IVM) has been applied is polycystic ovarian syndrome. In a concise review we present the techniques used for the IVM of oocytes and the role of hormones and growth factors in IVM and subsequent fertilization and early embryonic development. © 2006 New York Academy of Sciences

Effect of prolactin in the absence of hCG on maturation, fertilization, and embryonic development of in vitro matured mouse oocytes

Oocyte maturation is a complex process involving both the progression of meiotic cycle and the reprogramming of cytoplasmic events. The aim of this study was to investigate the effects of prolactin (PRL) in the in vitro maturation (IVM) of preantral mouse oocytes, in the absence of human chorionic gonadotrophin (hCG). Mouse preantral follicles were collected from female mice without prior hormonal ovarian stimulation and were cultured in the presence of varying concentrations of PRL (20, 100, 200, and 300 ng/mL) for 12 days. A group of in vitro matured oocytes were assessed for polar body (PB) formation, while the rest were fertilized and embryonic development was recorded. The maturation of preantral mouse follicles, as well as their fertilization and cleavage rates, observed when the culture mediumwas supplemented with middle- and high-range doses of PRL was beneficially affected. This effect was considerably high, although the culture media lacked hCG, a hormone extensively used in modern ovulation induction regiments, as well as in IVM media. © 2006 New York Academy of Sciences

Corticotropin-releasing hormone inhibits in vitro oocyte maturation in mice

The expression of corticotropin-releasing hormone (CRH) receptor 1 messenger RNA in stages of follicle growth was examined by reverse transcriptase-polymerase chain reaction in long-term cultures of early preantral mouse follicles with and without CRH addition. Corticotropin-releasing hormone receptor 1 is present in stages of mouse follicle growth, whereas 10 -9, 10-7, and 10-6 mol/L CRH inhibits oocyte maturation in vitro, an effect reversed by antalarmin addition. © 2011 American Society for Reproductive Medicine, Published by Elsevier Inc

Effect of PRL on in vitro follicle growth, in vitro oocyte maturation, fertilization and early embryonic development in mice

Prolactin (PRL), along with other hormones, plays a role in oocyte maturation, fertilization, and early embryonic development in mammals. In order to investigate the role of PRL on in vitro oocyte maturation from early follicular growth stages, as well as on fertilization and early embryonic development, we cultured preantral mouse follicles with and without PRL, followed by fertilization of the in vitro matured oocytes. Prolactin significantly improved the rate of oocyte maturation, fertilization, and early embryo development. Four isoforms of PRL-Receptor (R) have been found in whole ovaries of mice: one long (PRL-RL) and three short (-RS1, -RS 2, and -RS3). We examined expression of the four PRL-R isoforms in preantral follicles, in cumulus-oocyte complexes (COCs) and in germinal vesicle GV stage oocytes by RT-PCR. Prolactin-RL, -RS2 and -RS3 mRNA, but not -RS1, were expressed in preantral follicles, COCs, and GV stage oocytes. Our results indicate the prolactin pathway is functional in early preantral follicles, in COCs and in GV stage oocytes, and promotes oocyte maturation, meiosis, fertilization, and early embryonic development. © Copyright 2009, Mary Ann Liebert, Inc

Prolactin receptor mRNA expression in oocytes and preimplantation mouse embryos

Prolactin was first identified as an anterior pituitary lobe hormone, responsible for the regulation of mammary gland growth and development. Prolactin receptors have been localized in a number of peripheral tissues, including tissues involved in reproduction. Studies with knockout animals have shown that prolactin receptor deficient mice present reproductive defects, whereas prolactin promotes the developmental potential of preimplantation mouse and rat embryos in vitro. To better understand the role of prolactin in the process of reproduction and early embryo development in mice, the expression of the four transcript variants of prolactin receptor was examined in the first stages of mouse embryo development. Prolactin long receptor mRNA was expressed in all stages examined, that is in cumulus cells, oocytes, zygotes, 2-cell embryos, 4-cell embryos, morulae and blastocysts. Prolactin receptor type SI mRNA was observed only in cumulus cells, while S2 mRNA was present in cumulus cells, oocytes, zygotes and 2-cell embryos. S3 mRNA was expressed only in cumulus cells and oocytes. These results indicate that different isoforms of prolactin receptors may be present in the various stages of mouse preimplantation embryo and may play an important role in the control of its growth and development