Medicine and Health Sciences Commons^™

Expression And Localization Of Nrf2/Keap1 Signalling Pathway Genes In Mouse Preimplantation Embryos Exposed To Free Fatty Acids., Grace Dionne, Michele D. Calder, Dean H Betts, Basim Abu Rafea, Andrew J Watson

Obstetrics & Gynaecology Publications

Obese women experience greater incidence of infertility, with reproductive tracts exposing preimplantation embryos to elevated free fatty acids (FFA) such as palmitic acid (PA) and oleic acid (OA). PA treatment impairs mouse preimplantation development in vitro, while OA co-treatment rescues blastocyst development of PA treated embryos. In the present study, we investigated the effects of PA and OA treatment on NRF2/Keap1 localization, and relative antioxidant enzyme (Glutathione peroxidase; Gpx1, Catalase; Cat, Superoxide dismutase; Sod1 and γ-Glutamylcysteine ligase catalytic unit; Gclc) mRNA levels, during in vitro mouse preimplantation embryo development. Female mice were superovulated, mated, and embryos cultured in the presence …

Highlighting The Mechanistic Relationship Between Perinatal Depression And Preeclampsia: A Scoping Review, Mei Yuan, Samantha Bedell, Barbra De Vrijer, Genevieve Eastabrook, Jefferson C. Frisbee, Stephanie J. Frisbee

Obstetrics & Gynaecology Publications

Background: Although there is scientific literature supporting an association between depression and preeclampsia (PE), little is known about the underlying mechanistic pathways that may explain these observed associations. Thus, this study aimed to outline the relationship between depression and PE, and to highlight the underlying cardiovascular and metabolic risk factors that are common to both. Methods: A scoping review of the literature was conducted in Medline, Scopus, and Web of Science. Results: From 706 articles initially identified, 23 articles met the inclusion criteria and were included in this review. Although some studies reported a positive association between PE and postpartum …

Gestational Age Impacts Birth To Placental Weight Ratio And Umbilical Cord Oxygen Values With Implications For The Fetal Oxygen Margin Of Safety, Bryan S Richardson, Barbra De Vrijer, Hilary K Brown, Larry Stitt, Sheryl Choo, Timothy R H Regnault

Obstetrics & Gynaecology Publications

Background: We determined the impact of gestational age (GA) from near term to term to post-term on birth/placental weight ratio and cord oxygen values with implications for placental transport efficiency for oxygen, fetal O2 consumption relative to delivery or fractional O2 extraction, and oxygen margin of safety.

Materials and methods: A hospital database was used to obtain birth/placental weight ratios, cord PO2 and other information on patients delivering between Jan 1, 1990 and Jun 15, 2011 with GA > 34 completed weeks (N=69,852). Oxygen saturation was calculated from the cord PO2 and pH data, while fractional O2 extraction was calculated from …

Water-Fat Magnetic Resonance Imaging Of Adipose Tissue Compartments In The Normal Third Trimester Fetus, Stephanie A Giza, Tianna L Koreman, Simran Sethi, Michael R Miller, Debbie A Penava, Genevieve D Eastabrook, Charles A Mckenzie, Barbra De Vrijer

Obstetrics & Gynaecology Publications

BACKGROUND: Assessment of fetal adipose tissue gives information about the future metabolic health of an individual, with evidence that the development of this tissue has regional heterogeneity.

OBJECTIVE: To assess differences in the proton density fat fraction (PDFF) between fetal adipose tissue compartments in the third trimester using water-fat magnetic resonance imaging (MRI).

MATERIALS AND METHODS: Water-fat MRI was performed in a 1.5-T scanner. Fetal adipose tissue was segmented into cheeks, thorax, abdomen, upper arms, forearms, thighs and lower legs. PDFF and R2* values were measured in each compartment.

RESULTS: Twenty-eight women with singleton pregnancies were imaged between 28 and …

Effects Of Maternal Obesity And Gestational Diabetes Mellitus On The Placenta: Current Knowledge And Targets For Therapeutic Interventions, Samantha Bedell, Janine Hutson, Barbra De Vrijer, Genevieve Eastabrook

Obstetrics & Gynaecology Publications

Obesity and gestational diabetes mellitus (GDM) are becoming more common among pregnant women worldwide and are individually associated with a number of placenta-mediated obstetric complications, including preeclampsia, macrosomia, intrauterine growth restriction and stillbirth. The placenta serves several functions throughout pregnancy and is the main exchange site for the transfer of nutrients and gas from mother to fetus. In pregnancies complicated by maternal obesity or GDM, the placenta is exposed to environmental changes, such as increased inflammation and oxidative stress, dyslipidemia, and altered hormone levels. These changes can affect placental development and function and lead to abnormal fetal growth and development …

Maternal Obesity Reduces Placental Autophagy Marker Expression In Uncomplicated Pregnancies, Matthew Cohen, Emily Guo, Aidan Pucchio, Barbra De Vrijer, Trevor G Shepherd, Genevieve Eastabrook

Obstetrics & Gynaecology Publications

AIM: Obesity has been associated with changes in autophagy and its increasing prevalence among pregnant women is implicated in higher rates of placental-mediated complications of pregnancy such as pre-eclampsia and intrauterine growth restriction. Autophagy is involved in normal placentation, thus changes in autophagy may lead to impaired placental function and development. The aim of this study was to investigate the connection between obesity and autophagy in the placenta in otherwise uncomplicated pregnancies.

METHODS: Immunohistochemistry and western blot analysis were done on placental and omental samples from obese (body mass index [BMI] ≥30 kg/m

RESULTS: As pre-pregnancy BMI increased, there was …

Labour Progression In Obese Women: Are Women With Increased Body Mass Index Having Unnecessary Cesarean Sections?, Caroline Shenouda, Aloka Wijesooriya, Amanda Toufeili, Michael R Miller, Debbie Penava, Barbra De Vrijer

Obstetrics & Gynaecology Publications

OBJECTIVE: This study sought to determine whether obese pregnant women undergo cesarean sections without an adequate trial of labour. This may affect future birth and pregnancy outcomes.

METHODS: A retrospective analysis was done on 526 parturients at Victoria Hospital in London, Ontario. Women were categorized according to parity and pre-pregnancy body mass index (BMI; normal weight, BMI 18.5-24.9 kg/m

RESULTS: Obese class II and III primiparous women required an additional 1.62 and 2.67 hours (P = 0.012), respectively, to reach a dilation of 10 cm compared with their normal weight counterparts; obese class II and III multiparous women required an …

Implantation Failure In Female Kiss1-/- Mice Is Independent Of Their Hypogonadic State And Can Be Partially Rescued By Leukemia Inhibitory Factor., Michele Calder, Yee-Ming Chan, Renju Raj, Macarena Pampillo, Adrienne Elbert, Michelle Noonan, Carolina Gillio-Meina, Claudia Caligioni, Nathalie G Bérubé, Moshmi Bhattacharya, Andrew J Watson, Stephanie B Seminara, Andy V Babwah

Obstetrics & Gynaecology Publications

The hypothalamic kisspeptin signaling system is a major positive regulator of the reproductive neuroendocrine axis, and loss of Kiss1 in the mouse results in infertility, a condition generally attributed to its hypogonadotropic hypogonadism. We demonstrate that in Kiss1(-/-) female mice, acute replacement of gonadotropins and estradiol restores ovulation, mating, and fertilization; however, these mice are still unable to achieve pregnancy because embryos fail to implant. Progesterone treatment did not overcome this defect. Kiss1(+/-) embryos transferred to a wild-type female mouse can successfully implant, demonstrating the defect is due to maternal factors. Kisspeptin and its receptor are expressed in the mouse …

Stress-Inducible Phosphoprotein 1 Has Unique Cochaperone Activity During Development And Regulates Cellular Response To Ischemia Via The Prion Protein., Flavio H Beraldo, Iaci N Soares, Daniela F Goncalves, Jue Fan, Anu A Thomas, Tiago G Santos, Amro H Mohammad, Martin Roffé, Michele D Calder, Simona Nikolova, Glaucia N Hajj, Andre L Guimaraes, Andre R Massensini, Ian Welch, Dean H Betts, Robert Gros, Maria Drangova, Andrew J Watson, Robert Bartha, Vania F Prado, Vilma R Martins, Marco A M Prado

Obstetrics & Gynaecology Publications

Stress-inducible phosphoprotein 1 (STI1) is part of the chaperone machinery, but it also functions as an extracellular ligand for the prion protein. However, the physiological relevance of these STI1 activities in vivo is unknown. Here, we show that in the absence of embryonic STI1, several Hsp90 client proteins are decreased by 50%, although Hsp90 levels are unaffected. Mutant STI1 mice showed increased caspase-3 activation and 50% impairment in cellular proliferation. Moreover, placental disruption and lack of cellular viability were linked to embryonic death by E10.5 in STI1-mutant mice. Rescue of embryonic lethality in these mutants, by transgenic expression of the …

P38 Mapk Regulates Cavitation And Tight Junction Function In The Mouse Blastocyst., Christine E Bell, Andrew J Watson

Obstetrics & Gynaecology Publications

UNLABELLED: Blastocyst formation is essential for implantation and maintenance of pregnancy and is dependent on the expression and coordinated function of a series of proteins involved in establishing and maintaining the trans-trophectoderm ion gradient that enables blastocyst expansion. These consist of Na/K-ATPase, adherens junctions, tight junctions (TJ) and aquaporins (AQP). While their role in supporting blastocyst formation is established, the intracellular signaling pathways that coordinate their function is unclear. The p38 MAPK pathway plays a role in regulating these proteins in other cell types and is required for embryo development at the 8-16 cell stage, but its role has not …

Culture Medium, Gas Atmosphere And Mapk Inhibition Affect Regulation Of Rna-Binding Protein Targets During Mouse Preimplantation Development., Michele D Calder, Patricia H Watson, Andrew J Watson

Obstetrics & Gynaecology Publications

During oogenesis, mammalian oocytes accumulate maternal mRNAs that support the embryo until embryonic genome activation. RNA-binding proteins (RBP) may regulate the stability and turnover of maternal and embryonic mRNAs. We hypothesised that varying embryo culture conditions, such as culture medium, oxygen tension and MAPK inhibition, affects regulation of RBPs and their targets during preimplantation development. STAU1, ELAVL1, KHSRP and ZFP36 proteins and mRNAs were detected throughout mouse preimplantation development, whereas Elavl2 mRNA decreased after the two-cell stage. Potential target mRNAs of RBP regulation, Gclc, Slc2a1 and Slc7a1 were detected during mouse preimplantation development. Gclc mRNA was significantly elevated in embryos …

Ouabain Stimulates A Na+/K+-Atpase-Mediated Sfk-Activated Signalling Pathway That Regulates Tight Junction Function In The Mouse Blastocyst., Holly Giannatselis, Michele Calder, Andrew J Watson

Obstetrics & Gynaecology Publications

The Na(+)/K(+)-ATPase plays a pivotal role during preimplantation development; it establishes a trans-epithelial ionic gradient that facilitates the formation of the fluid-filled blastocyst cavity, crucial for implantation and successful pregnancy. The Na(+)/K(+)-ATPase is also implicated in regulating tight junctions and cardiotonic steroid (CTS)-induced signal transduction via SRC. We investigated the expression of SRC family kinase (SFK) members, Src and Yes, during preimplantation development and determined whether SFK activity is required for blastocyst formation. Embryos were collected following super-ovulation of CD1 or MF1 female mice. RT-PCR was used to detect SFK mRNAs encoding Src and Yes throughout preimplantation development. SRC and …

Mitogen-Activated Protein Kinase (Mapk) Pathways Mediate Embryonic Responses To Culture Medium Osmolarity By Regulating Aquaporin 3 And 9 Expression And Localization, As Well As Embryonic Apoptosis., Christine E Bell, Nathalie M K Larivière, Patricia H Watson, Andrew J Watson

Obstetrics & Gynaecology Publications

BACKGROUND: In order to advance the development of culture conditions and increase the potential for supporting normal preimplantation embryo development in vitro, it is critical to define the mechanisms that early embryos utilize to survive in culture. We investigated the mechanisms that embryos employ in response to culture medium osmolarity. We hypothesized that mitogen-activated protein kinase (MAPK) pathways mediate responses to hyperosmotic stress by regulating Aquaporin (AQP) 3 and 9 expression as well as embryonic apoptosis.

METHODS: Real-time reverse transcription and polymerase chain reaction and whole-mount immunofluorescence were used to determine the relative mRNA levels and protein localization patterns of …

Preimplantation Embryo Programming: Transcription, Epigenetics, And Culture Environment., Veronique Duranthon, Andrew J Watson, Patrick Lonergan

Obstetrics & Gynaecology Publications

Preimplantation development directs the formation of an implantation- or attachment-competent embryo so that metabolic interactions with the uterus can occur, pregnancy can be initiated, and fetal development can be sustained. The preimplantation embryo exhibits a form of autonomous development fueled by products provided by the oocyte and also from activation of the embryo's genome. Despite this autonomy, the preimplantation embryo is highly influenced by factors in the external environment and in extreme situations, such as those presented by embryo culture or nuclear transfer, the ability of the embryo to adapt to the changing environmental conditions or chromatin to become reprogrammed …

Mouse Preimplantation Embryo Responses To Culture Medium Osmolarity Include Increased Expression Of Ccm2 And P38 Mapk Activation., Barry Fong, Patricia H Watson, Andrew J Watson

Obstetrics & Gynaecology Publications

BACKGROUND: Mechanisms that confer an ability to respond positively to environmental osmolarity are fundamental to ensuring embryo survival during the preimplantation period. Activation of p38 mitogen-activated protein kinase (MAPK) occurs following exposure to hyperosmotic treatment. Recently, a novel scaffolding protein called Osmosensing Scaffold for MEKK3 (OSM) was linked to p38 MAPK activation in response to sorbitol-induced hypertonicity. The human ortholog of OSM is cerebral cavernous malformation 2 (CCM2). The present study was conducted to investigate whether CCM2 is expressed during mouse preimplantation development and to determine whether this scaffolding protein is associated with p38 MAPK activation following exposure of preimplantation …

P38 Mitogen-Activated Protein Kinase (Mapk) First Regulates Filamentous Actin At The 8-16-Cell Stage During Preimplantation Development., Andrew J M Paliga, David R Natale, Andrew J Watson

Obstetrics & Gynaecology Publications

BACKGROUND INFORMATION: The MAPK (mitogen-activated protein kinase) superfamily of proteins consists of four separate signalling cascades: the c-Jun N-terminal kinase or stress-activated protein kinases (JNK/SAPK); the ERKs (extracellular-signal-regulated kinases); the ERK5 or big MAPK1; and the p38 MAPK group of protein kinases, all of which are highly conserved. To date, our studies have focused on defining the role of the p38 MAPK pathway during preimplantation development. p38 MAPK regulates actin filament formation through the downstream kinases MAPKAPK2/3 (MAPK-activated protein kinase 2/3) or MAPKAPK5 [PRAK (p38 regulated/activated kinase)] and subsequently through HSP25/27 (heat-shock protein 25/27). We recently reported that 2-cell-stage murine …

P38 Mapk Signaling During Murine Preimplantation Development., David R Natale, Andrew J M Paliga, Frank Beier, S J A D'Souza, Andrew J Watson

Obstetrics & Gynaecology Publications

Mitogen-activated protein kinase (MAPK) pathways mediate some important cellular processes and are likely to also regulate preimplantation development. The role of p38 MAP kinase signaling during murine preimplantation development was investigated in the present study. p38 MAPK, p38-regulated or -activated kinase (PRAK; MK5), map kinase-activated protein kinase 2 (MK2), and heat shock protein 25 (hsp25) mRNAs and proteins were detected throughout preimplantation development. Two-cell stage embryos cultured in the presence of SB220025 and SB203580 (specific inhibitors of p38 MAPK alpha/beta), progressed to the eight-cell stage with the same frequency as controls; however, treated embryos halted their development at the 8- …

The Gamma-Subunit Of The Na-K-Atpase As A Potential Regulator Of Apical And Basolateral Na+-Pump Isozymes During Development Of Bovine Pre-Attachment Embryos., L C Barcroft, S E Gill, A J Watson

Obstetrics & Gynaecology Publications

Expression and activity of the Na-K-ATPase within the basolateral membrane domains of the trophectoderm epithelium provide the driving force for accumulation of Na(+) and Cl(-) across the nascent epithelium, mediating fluid movement into the forming blastocoel. Within the trophectoderm of the bovine blastocyst, multiple isozymes of the Na-K-ATPase are expressed. Immunolocalization has demonstrated that the alpha1-isozyme localizes within the basolateral membrane, whereas the alpha 3-isozyme localizes to the apical cell margins. Gene-specific RT-PCR and wholemount indirect immunofluorescence confocal laser scanning microscopy were used to examine expression of the Na-K-ATPase gamma-subunit (a regulatory subunit of the Na-K-ATPase) throughout development of bovine …

Sensitivity Of Bovine Blastocyst Gene Expression Patterns To Culture Environments Assessed By Differential Display Rt-Pcr., D R Natale, P A De Sousa, M E Westhusin, A J Watson

Obstetrics & Gynaecology Publications

The use of culture media to support the development of preimplantation embryos to the blastocyst stage is often associated with detrimental effects on normal development. These effects have been uncovered largely by investigating the phenotypic abnormalities displayed by fetuses and newborns derived from cultured preimplantation embryos. Research to understand the impact of culture on the embryonic developmental programme has focused on embryo metabolism, gene expression and genomic imprinting. We have used differential display RT-PCR to examine culture influences on global transcript pools in bovine embryos. Others have examined culture influences on candidate "marker genes" in cultured murine, ovine and bovine …

Mrnas Encoding Aquaporins Are Present During Murine Preimplantation Development., H Offenberg, L C Barcroft, A Caveney, D Viuff, P D Thomsen, A J Watson

Obstetrics & Gynaecology Publications

The present study was conducted to investigate the mechanisms underlying fluid movement across the trophectoderm during blastocyst formation by determining whether aquaporins (AQPs) are expressed during early mammalian development. AQPs belong to a family of major intrinsic membrane proteins and function as molecular water channels that allow water to flow rapidly across plasma membranes in the direction of osmotic gradients. Ten different AQPs have been identified to date. Murine preimplantation stage embryos were flushed from the oviducts and uteri of superovulated CD1 mice. Reverse transcription-polymerase chain reaction (RT-PCR) methods employing primer sets designed to amplify conserved sequences of AQPs (1-9) …

Effects Of Superovulated Heifer Diet Type And Quantity On Relative Mrna Abundances And Pyruvate Metabolism In Recovered Embryos., C Wrenzycki, P De Sousa, E W Overström, R T Duby, D Herrmann, A J Watson, H Niemann, D O'Callaghan, M P Boland

Obstetrics & Gynaecology Publications

This study investigated the effects of quantity and type of diet fed to superovulated donor heifers on molecular and metabolic indices of embryonic development. These effects included the relative abundances of mRNAs for the alpha 1 subunit of Na/K-ATPase and the antioxidant enzyme Cu/Zn-SOD, as well as pyruvate utilization in bovine morulae and blastocysts developed in vivo. Heifers were fed a daily ration of either grass silage and a citrus-beet pulp-based concentrate or grass silage and a barley-based concentrate for 116 days, both at 3 kg per day or ad libitum. In embryos derived from heifers fed the pulp-based diets, …

Igf Paracrine And Autocrine Interactions Between Conceptus And Oviduct., A J Watson, M E Westhusin, Q A Winger

Obstetrics & Gynaecology Publications

Development in vitro is influenced by embryo density, serum, somatic cell co-culture and the production of 'embryotrophic' paracrine and autocrine factors. Research in our laboratory has focussed principally on the insulin-like growth factor (IGF) family. We have demonstrated that pre-attachment bovine and ovine embryos express mRNAs encoding a number of growth factor ligand and receptor genes including all members of the IGF ligand and receptor family throughout this developmental interval. In addition, early embryos express mRNAs encoding IGF-binding proteins (IGFBPs) 2-5 from the one-cell to the blastocyst stage and IGFBP5 mRNA at the blastocyst stage. Cultured bovine blastocysts release up …

Transient Expression Of A Translation Initiation Factor Is Conservatively Associated With Embryonic Gene Activation In Murine And Bovine Embryos., P A De Sousa, A J Watson, R M Schultz

Obstetrics & Gynaecology Publications

In the present study the abundance of mRNAs for eukaryotic translation initiation factors eIF-1A (formerly known as eIF-4C), -2alpha, -4A, -4E, and -5 was examined in in vivo-derived mouse embryos throughout preimplantation development using a semiquantitative reverse transcription-polymerase chain reaction assay. Although the mRNA profile for each gene is unique, only mRNA for eIF-1A transiently increases during embryonic gene activation (EGA) at the 2-cell stage, and this was confirmed by an independent hybridization-based assay. In in vitro-developed bovine embryos, mRNA for eIF-1A was transiently detected at the 8-cell stage, when the major activation of the genome occurs in this species. …

Na/K-Atpase-Mediated 86rb+ Uptake And Asymmetrical Trophectoderm Localization Of Alpha1 And Alpha3 Na/K-Atpase Isoforms During Bovine Preattachment Development., D H Betts, L C Barcroft, A J Watson

Obstetrics & Gynaecology Publications

This study evaluated Na/K-ATPase alpha 1- and alpha 3-subunit isoform polypeptide expression and localization during bovine preattachment development. Na/K-ATPase cation transport activity from the one-cell to blastocyst stage was also determined by measuring ouabain-sensitive 86Rb+ uptake. Both alpha1- and alpha 3-subunit polypeptides were detected by immunofluorescence to encircle the entire cell margins of each blastomere of inseminated zygotes, cleavage stage embryos, and morulae. Immunofluorescent localization of alpha1-subunit polypeptide in bovine blastocysts revealed an alpha1 immunofluorescence signal confined to the basolateral membrane margins of the trophectoderm and encircling the cell periphery of each inner cell mass (ICM) cell. In contrast, alpha …

A Growth Factor Phenotype Map For Ovine Preimplantation Development., A J Watson, P H Watson, M Arcellana-Panlilio, D Warnes, S K Walker, G A Schultz, D T Armstrong, R F Seamark

Obstetrics & Gynaecology Publications

The reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the patterns of expression for several growth factor ligand and receptor genes during ovine preimplantation development. Transcripts for insulin-like growth factor (IGF)-I, IGF-II, and the receptors for insulin and IGF-I were detected throughout ovine preimplantation development from the 1-cell to the blastocyst stage. Transforming growth factor alpha (TGF alpha) transcripts were also detected throughout ovine preimplantation development. The mRNAs encoding basic fibroblast growth factor (bFGF) were detected in all stages of the ovine preimplantation embryo, although the relative abundance of this transcript consistently decreased from the 1-cell to the blastocyst …

Preimplantation Development Of In Vitro-Matured And In Vitro-Fertilized Ovine Zygotes: Comparison Between Coculture On Oviduct Epithelial Cell Monolayers And Culture Under Low Oxygen Atmosphere., A J Watson, P H Watson, D Warnes, S K Walker, D T Armstrong, R F Seamark

Obstetrics & Gynaecology Publications

The roles of medium composition, serum source, embryo coculture, and culture under low O2 conditions on the development of in vitro-matured and in vitro-fertilized (IVMF) ovine zygotes were investigated in three separate experiments. In the first experiment, the proportion of cocultured IVMF zygotes developing to the blastocyst stage was significantly higher (38.0% vs. 3.5%; p < 0.05) than that of non-cocultured zygotes treated within three embryo culture media (TCM-199 + 10% fetal bovine serum [FBS]; bicarbonate-buffered, glucose-free synthetic oviduct fluid medium [mod-SOFM] + 10% FBS; and bicarbonate-buffered BSA-free Tyrode's salt solution [mod-TALP] + 10% FBS) under a 5% CO2 atmosphere in air. In a second experiment, a significantly higher (p < 0.05) proportion of cocultured zygotes placed in TCM-199 medium survived to the blastocyst stage (37.4% blastocysts vs. 23.4% in mod-SOFM). No significant effect of serum (FBS vs. human serum [HS]) was observed on embryonic development, but coculture was confirmed to exert a significant influence on development to the blastocyst stage. In the final experiment, survival of the embryo under a reduced oxygen (5% CO2:5% O2:90% N2) atmosphere was investigated. In contrast to results in the initial experiments, embryonic survival was significantly higher (p < 0.05) in the non-cocultured treatment groups (21.9% blastocysts vs. 0.4% for cocultured zygotes). Serum source also had a significant (p < 0.05) influence upon the development of non-cocultured zygotes: 32.3% of zygotes cultured with HS progressed to the blastocyst stage vs. 11.5% of zygotes cultured in FBS-supplemented medium. These results have characterized two distinct culture environments, each capable of supporting the development of high frequencies of unselected IVMF zygotes to the blastocyst stage in vitro.

Possible Roles Of Insulin And Insulin-Like Growth Factors In Rat Preimplantation Development: Investigation Of Gene Expression By Reverse Transcription-Polymerase Chain Reaction., X Zhang, G M Kidder, A J Watson, G A Schultz, D T Armstrong

Obstetrics & Gynaecology Publications

The sensitive mRNA phenotyping technique of reverse transcription-polymerase chain reaction was used to demonstrate that insulin receptor mRNA is present in rat embryos during the preimplantation period. In addition, mRNA encoding insulin-like growth factor (IGF) type I and type II receptors have also been detected in rat preimplantation embryos. IGF-I mRNA was not detected in preimplantation embryos but was found in oviducts and uteri of prepubertal and early pregnant rats. IGF-II mRNA was present in both embryos and in oviducts and uteri during the preimplantation period. These findings suggest that insulin and IGF-I could influence early embryo development in endocrine …