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Eicosanoid Binding Sites in Ovarian and Uterine Tissues
Published in Murray D. Mitchell, Eicosanoids in Reproduction, 2020
PGE2 is an embryonic signal in the maternal recognition of pregnancy in some animal species.57 This signal involves maintenance of the corpus luteum function for successful continuation of pregnancy.
The Signaling between Embryo and Mother as a Basis for the Development of Tolerance
Published in Howard J.A. Carp, Recurrent Pregnancy Loss, 2020
In mammalian gestation, immunologic acceptance and tolerance are paramount for the successful interaction between the embryo/graft and its maternal host. Initial immunologic awareness must take place prior to implantation. The semipermeable zona pellucida forms rapidly post fertilization and protects the embryo until it reaches the endometrium. The zona is surrounded by maternal immune cells, and this unit transmits the message that fertilization has occurred. However, in in vitro fertilization (IVF) and embryo transfer this mechanism is not operative. The main question is when and how the embryo-maternal communication initiates and creates maternal recognition of pregnancy. Advances in assisted reproduction suggest that the embryo is the dominant element in the reproductive process; its viability and ability to signal are critical for embryo-maternal recognition. Furthermore, genetics does not appear to play a predominant role; donor embryos or xeno-transfer embryos fare very well following transfer with no discernable difference to semi-allogenic embryos.
Reproductive System and Mammary Gland
Published in Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard, Toxicologic Pathology, 2018
Justin D. Vidal, Charles E. Wood, Karyn Colman, Katharine M. Whitney, Dianne M. Creasy
The menstrual cycle of the NHP typically lasts between 28 and 32 days with ovulation at the midway point around day 14, similar to the human menstrual cycle. During the first half of the cycle, the follicular phase, there are low levels of gonadotropins and rising levels of estradiol stemming from the developing dominant follicle (Weinbauer et al. 2008; Zeleznik and Pohl 2006). Inhibin B levels are highest during the early follicular phase and decrease as ovulation approaches (Fraser et al. 1999; Shimizu et al. 2002). Estradiol levels continue to rise until around day 12, followed by a sharp increase in FSH and LH levels leading to ovulation of the Graafian follicle (Weinbauer et al. 2008; Zeleznik and Pohl 2006). During this periovulatory period, progesterone levels begin to rise and may play a role in oocyte maturation, ovulation, and luteinization (Borman et al. 2004; Chaffin and Stouffer 2002). After ovulation, the luteal phase begins, estradiol and gonadotropin levels decrease rapidly, and progesterone and inhibin A levels continue to rise as the corpus luteum develops (Suresh and Medhamurthy 2009). During the luteal phase, gonadotropin levels remain low and, unlike the human, NHPs do not show a consistent elevation in luteal phase estradiol levels (Shimizu 2008; Weinbauer et al. 2008). Circulating progesterone reaches a maximum level around day 22 and in the absence of maternal recognition of pregnancy, corpus luteum function declines and the menstrual phase begins (Weinbauer et al. 2008). During the menstrual phase, progesterone and inhibin A levels decrease and there is a brief increase in FSH levels to support follicular recruitment for the next cycle (Gougeon 1996; Jabbour et al. 2006; Weinbauer et al. 2008; Zeleznik and Pohl 2006).
Role of preovulatory concentrations of estradiol on timing of conception and regulation of the uterine environment in beef cattle
Published in Systems Biology in Reproductive Medicine, 2020
George A. Perry, Robert A. Cushman, Brandi L. Perry, Amanda K. Schiefelbein, Emmalee J. Northrop, Jerica J.J. Rich, Stephanie D. Perkins
During the estrous cycle, the endometrium undergoes changes in composition and differentiation status. These changes are mainly regulated by estradiol, progesterone, and oxytocin (Spencer et al. 2004), and expression of uterine oxytocin and steroid receptors change throughout the estrous cycle (Robinson et al. 2001). Thus, the uterine environment changes dynamically during the estrous cycle, and this environment plays a vital role in maternal recognition of pregnancy, elongation, and attachment through secretion of nutrients, growth factors, immunosuppressive agents, enzymes, and ions that are necessary for proper embryonic growth and development (Geisert et al. 1992; Gray et al. 2001). More specifically, whether or not an animal was exposed to elevated concentrations of estradiol has been reported to impact gene expression within the endometrium (Bridges et al. 2012b). Estradiol-induced expression of endometrial receptors, production of uterine proteins (Bartol et al. 1981), and also influenced the expression of many genes involved in uterine extracellular matrix remodeling (Bauersachs et al. 2005). Bridges et al. (2012b) determined nuclear progesterone receptors in the deep glandular epithelium and mRNA abundance of ERα in the uterine epithelium was decreased among animals that had decreased preovulatory estradiol concentrations compared to animals that were exposed to elevated estradiol concentrations during the preovulatory period on d 15 after insemination. On d 19 after insemination, Davoodi et al. (2016) reported that genes associated with maternal immune system suppression (IGLL1, CXCL10, MX2, SLPI), attachment between the endometrium and conceptus (MMP19, MYL12A), and CL maintenance (OXT, COX2, FPr, CYP11A, BAX) were favorably expressed in cows that exhibited estrus near the time of AI.
Current status of sperm functional genomics and its diagnostic potential of fertility in bovine (Bos taurus)
Published in Systems Biology in Reproductive Medicine, 2018
Sellappan Selvaraju, Sivashanmugam Parthipan, Lakshminarayana Somashekar, B. Krishnan Binsila, Atul P. Kolte, Arunachalam Arangasamy, Janivara Parameshwaraiah Ravindra, Stephen A. Krawetz
Seminal proteins help the spermatozoa to reach, recognize, and fertilize the oocyte (Selvaraju et al. 2015; Somashekar et al. 2015, 2017; [reviewed in (Harayama et al. 2017)]). The seminal plasma components describe the characteristics of spermatogenesis and sperm maturation events prior to fertilization (Selvaraju et al. 2015). The addition of heparin and gelatin-binding seminal plasma proteins to the caudal epididymal spermatozoa improved the sperm functional membrane integrity and the ability of the spermatozoa to penetrate the cervical mucus (Arangasamy et al. 2005). Since spermatozoa lack the transcription and translation efficiency (Gur and Breitbart 2006), seminal proteome gains prime importance to assess the fertilization competence of spermatozoa. Though the influence of seminal plasma proteins on sperm fertilization competence has been established (Arangasamy et al. 2005; Selvaraju et al. 2015; Somashekar et al. 2015, 2017), the molecular actions of these proteins within the female reproductive tract for establishing successful pregnancy need to be studied (Schjenken and Robertson 2014; Somashekar et al. 2017). The immunoregulatory molecules in the seminal components modulate uterine cytokines and chemokines transcription during the pre- and post-implantation period for enhancing the implantation success during the critical period of maternal recognition of pregnancy (Ibrahim 2017). Recent studies indicated that the seminal plasma components such as nerve growth factor-β enhanced corpus lutem function and could play a role in conceptus development in bovine (Tanco et al. 2012; Stewart et al. 2017). However, the role of seminal plasma in establishing successful pregnancy in mammals is controversial (Pfeiffer et al. 2012). The effect of seminal proteins on the development of offspring phenotype has been reported in insects (Michaud et al. 2013) and mice (Bromfield et al. 2014), but not in bovine.