Biology of reproduction.
Publisher:
Society for the Study of Reproduction. New York : Oxford University Press (2017)
Frequency: Monthly
Country: United States
Language: English
Author(s):
Society for the Study of Reproduction.
Start Year:1969 -
ISSN:
0006-3363 (Print)
1529-7268 (Electronic)
0006-3363 (Linking)
1529-7268 (Electronic)
0006-3363 (Linking)
Impact Factor
3.6
2022
| NLM ID: | 0207224 |
| (DNLM): | B17900000(s) |
| (OCoLC): | 01536448 |
| Coden: | BIREBV |
| Classification: | W1 BI852N |
Glutathione-independent prostaglandin D2 synthase in ram and stallion epididymal fluids: origin and regulation. Microsequencing after two-dimensional electrophoresis revealed a major protein, glutathione-independent prostaglandin D2 synthase (PGDS) in the anterior epididymal region fluid of the ram and stallion. In this epididymal region, PGDS was a polymorphic compound with a molecular mass around 30 kDa and a range of pI from 4 to 7. PGDS represented 15% and 8% of the total luminal proteins present in this region in the ram and stallion, respectively. The secretion of the protein as judged by in vitro biosynthesis, and the presence of its mRNA as studied by Northern blot analysis, were limited to the ...
Scrotal heat stress induces altered sperm chromatin structure associated with a decrease in protamine disulfide bonding in the stallion. A variety of testicular insults can induce changes in the structure of spermatozoal chromatin, resulting in spermatozoal DNA that is more susceptible to acid-induced denaturation. The degree of change in the DNA can be measured using the sperm chromatin structure assay (SCSA). The SCSA measures the relative amounts of single- and double-stranded DNA after staining with the metachromatic dye, acridine orange. Here we used a stallion model (n = 4) to study the effects of scrotal heat stress on spermatozoal DNA. This model was created by insulating stallion testes for 48 h and collecting sperm da...
Production of gelatinases and tissue inhibitors of matrix metalloproteinases by equine ovarian stromal cells In vitro. Matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) play very important roles in extracellular matrix (ECM) remodeling in ovarian follicle growth and ovulation. Equine follicles are embedded in cortex that is at the center of the ovary, and they must expand/emigrate to the fossa, the only site in the ovary for ovulation. Therefore, equine ovarian stromal cells (EOSC) are probably involved in ECM remodeling during follicle growth. This study examined whether cultured EOSC synthesize gelatinases and TIMPs, molecules essential for ECM remodeling in other systems. Results showed...
Inhibin secretion in the mare: localization of inhibin alpha, betaA, and betaB subunits in the ovary. To determine the source of circulating inhibin and estradiol-17beta during the estrous cycle in mares, the cellular localization of the inhibin alpha, betaA, and betaB subunits and aromatase in the ovary was determined by immunohistochemistry. Concentrations of immunoreactive (ir-) inhibin, estradiol-17beta, progesterone, LH, and FSH in peripheral blood were also measured during the estrous cycle in mares. Immunohistochemically, inhibin alpha subunits were localized in the granulosa cells of small and large follicles and in the theca interna cells of large follicles, whereas inhibin betaA and ...
Gonadotropin response to naloxone in the mare: effect of time of year and reproductive status. In the mare, endogenous opioids have been implicated in the suppression of gonadotropin secretion during seasonal anestrus (AN). The present study tested whether continuation of reproductive activity during the nonbreeding season (NBS) reflects the absence of a seasonal shift in opioid tone compared to what occurs in AN mares. During the NBS, 11 AN and 8 luteal-phase mares received 0.1, 0.05, 0. 025 mg/kg naloxone (NAL) or vehicle on alternate days. Whereas cycling mares responded to all dosages of NAL, AN mares responded only to the higher dosages for FSH, and LH failed to increase at any dos...
Equine chorionic gonadotropin regulates luteal steroidogenesis in pregnant mares. The onset of eCG secretion in pregnant mares coincides with an increase in luteal steroid production and a relative shift toward androgen and estrogen synthesis. However, a cause-effect relationship between eCG and the shift in luteal steroidogenesis has not been demonstrated. In this study, we have investigated the effect of eCG on steroid production by the corpus luteum (CL) during equine pregnancy. All mares were supplemented with 44 mg altrenogest (a progestogen) per day on Days 18-50. Increasing doses of eCG were administered on Days 26-28, before the onset of endogenous eCG secretion, to...
Progesterone-induced acrosome reaction in stallion spermatozoa is mediated by a plasma membrane progesterone receptor. The aim of the present study was to investigate whether the induction of stallion sperm acrosome reaction (AR) by progesterone is mediated by binding of progesterone to a receptor on the sperm plasma membrane or to an intracellular progesterone receptor. Progesterone-BSA conjugate labeled with fluorescein isothiocyanate (P-BSA-FITC) in combination with a vital stain, ethidium homodimer, was applied to visualize the presence of the progesterone receptor on living spermatozoa. Alternatively, an indirect immunofluorescence technique employing a monoclonal antibody (C-262) against human intracellu...
Transfer of a uterine lipocalin from the endometrium of the mare to the developing equine conceptus. One of the major, progesterone-dependent proteins secreted into the uterine lumen of the mare is a 19-kDa lipocalin (P19). It associates strongly with the embryonic capsule that envelops the young horse conceptus in early gestation, suggesting that it may be involved in sustaining early development. However, it was not known whether the protein was transported through the capsule and/or trophoblast layer and into the yolk sac cavity. To address this question, polyclonal antisera were raised against a C-terminal peptide (based on the deduced amino acid sequence of P19) and a recombinant-derived...
Prostasome-like particles in stallion semen. Human semen contains membranous vesicles called prostasomes. They are secreted by the prostate gland and contain large amounts of cholesterol, sphingomyelin, and Ca2+. Prostasomes enhance the motility of ejaculated spermatozoa and are involved in a number of additional biological functions. No prostasome-like vesicles have been described in horse semen up to now. We have demonstrated the presence of prostasome-like vesicles in the equine semen and characterized them as to size, morphology, and lipid composition; we have found that they are similar to human prostasomes in many respects. We prop...
Oocyte competence for in vitro maturation is associated with histone H1 kinase activity and is influenced by estrous cycle stage in the mare. The in vitro maturation rate of equine oocytes remains low, regardless of culture conditions. Our objective was to determine the reasons for failure of equine oocytes to resume meiosis during in vitro maturation and to ascertain the influence of the estrous cycle stage on meiotic competence. In 10 cyclic mares, 7 ultrasound-guided follicular punctures were performed alternately during the follicular phase (group DF; n = 3 punctures), at the end of the follicular phase (group EF; n = 2), and during the luteal phase (group DL; n = 2). We evaluated the competence of the oocytes for in vitro matur...
Testicular inhibin in the stallion: cellular source and seasonal changes in its secretion. The cellular localization of inhibin alpha, betaA, and betaB subunits, 3beta-hydroxysteroid dehydrogenase (3beta-HSD), and cytochrome P450 aromatase (aromatase) in stallion testes was investigated. In addition, detailed seasonal changes in circulating immunoreactive (ir)-inhibin were investigated in correlation with testosterone, estradiol, LH, and FSH. Inhibin alpha subunit-positive staining was observed in Sertoli cells, and more clearly positive staining was noted in Leydig cells. Inhibin betaA and betaB subunits were also stained in both types of cells. Immunoreactivity of 3beta-HSD and ar...
Intrafollicular insulin-like growth factor-binding protein levels in equine ovarian follicles during preovulatory maturation and regression. The profiles of insulin-like growth factor-binding proteins (IGFBPs) in follicular fluid have been characterized in a number of mammals (rats, pigs, sheep, cattle, humans) and are good indicators of follicular status. We studied the IGFBP profiles of equine serum and ovarian follicular fluid recovered at various stages of the follicular phase. The levels of IGFBPs were related to the morphology and the steroidogenic activity of the follicles. Follicular fluids were recovered by ultrasound-guided follicular aspiration. In the first experiment, the dominant follicles of 10 mares were partly punc...
Chorionic gonadotropin secretion is associated with an inhibition of follicular growth and an improvement in oocyte competence for in vitro maturation in the mare. This study reports the follicular growth and oocyte competence for in vitro maturation and fertilization under the influence of circulating eCG. Three to 7 successive ultrasound-guided follicular punctures were performed on 4 pregnant mares from Day 23 until Day 75 of pregnancy and on 5 control mares whose embryonic vesicle was crushed on Day 22. All follicles larger than 5 mm were punctured 24 h after the largest follicle reached 18 mm. Expanded cumulus oocyte complexes (COCs) were stained at recovery to analyze the nuclear stage. Compact COCs were cultured in vitro for 46 h and either staine...
Intracytoplasmic sperm injection of in vitro-matured equine oocytes. Intracytoplasmic sperm injection (ICSI) was performed on equine oocytes matured in vitro. The oocytes were aspirated from abattoir ovaries and matured in vitro for 36 h at 38 degrees C. ICSI was performed using frozen/thawed stallion semen after swimup in medium containing human serum albumin. Sperm-injected oocytes were either 1) cultured in vitro for 10, 20, or 72 h; 2) transferred to oviducts of pseudopregnant mice; or 3) transferred to a synchronized mare after initial in vitro culture. The transferred ova were recovered after 72 h, and all ova were subsequently fixed, stained, and process...
Role of diameter differences among follicles in selection of a future dominant follicle in mares. Follicles > or = 5 mm were ablated in pony mares by a transvaginal ultrasound-guided technique on Day 10 (ovulation = Day 0). Follicle emergence (at 15 mm, experiment 1; at 6 mm, experiment 2) and development of the new wave was monitored by transrectal ultrasound. Deviation was defined as the beginning of a marked difference in growth rates between the two largest follicles. In experiment 1, mares were grouped (n = 4 per group) into controls, ablation-controls (ablations at Day 10 only), and a two-follicle model (periodic ablation sessions so that only the two largest follicles developed)....
Characterization of the equine glycoprotein hormone alpha-subunit gene reveals divergence in the mechanism of pituitary and placental expression. The equine glycoprotein hormone alpha-subunit gene is expressed in both pituitary and placenta, unlike that of all other nonprimate mammals studied, in which expression is limited to pituitary. Previous studies of the 5'-flanking region of the equine alpha-subunit promoter have revealed unique characteristics as well as similarities with the human alpha-subunit promoter, which demonstrates a similar pattern of tissue-specific expression. We have cloned and sequenced the equine alpha-subunit gene and have used tissue culture systems and transgenic mice to characterize its expression. Unlike the...
Evidence for the presence of sodium- and potassium-dependent adenosine triphosphatase alpha1 and beta1 subunit isoforms and their probable role in blastocyst expansion in the preattachment horse conceptus. The unusual hypotonicity of equine blastocyst fluid has prompted us to investigate the role of sodium- and potassium-dependent adenosine triphosphatase (Na+,K+-ATPase) in the process of fluid accumulation in the horse conceptus. Nine mares were used for the experiments. Reverse transcriptase polymerase chain reaction was conducted on two sets of five conceptuses recovered between 12 and 28 days (+/- 1 day) after ovulation. Messenger RNAs encoding the alpha1 and beta1 subunit isoforms of Na+,K+-ATPase were detected in all embryonic tissues examined. Western blot analysis showed that alpha1 and ...
Equine oocyte competence for nuclear and cytoplasmic in vitro maturation: effect of follicle size and hormonal environment. Equine oocyte competence after in vitro maturation (IVM) was investigated in terms of the diameter of the follicle of origin and the stage of the estrous cycle, with three criteria of maturation: nuclear stage after DNA Hoechst staining, meiotic spindle morphology after tubulin immunocytochemical staining, and cortical granule localization after lectin labeling. Seven successive in vivo ultrasound-guided follicular punctures were performed on 10 cyclic saddle mares, alternatively at the end of the follicular phase (after induction of ovulation with a gonadotropin injection) and in midluteal ph...
Relationships among oocyte-cumulus morphology, follicular atresia, initial chromatin configuration, and oocyte meiotic competence in the horse. Horse oocytes with expanded (EX) cumuli appear to have greater meiotic competence than do horse oocytes with compact (CP) cumuli but are thought to come from atretic follicles. We evaluated the relationships among cumulus expansion, follicle viability, initial chromatin configuration, and meiotic competence of horse oocytes. Follicle walls were sectioned for histological examination, and the follicles were scraped to obtain the oocytes. Half of the oocytes were evaluated immediately and half were matured for 24 h in vitro. Cumulus expansion was significantly associated with follicle atresia. I...
Comparison of the effects of N-methyl-DL-aspartic acid on gonadotropin and prolactin secretion in anestrous mares and mares exhibiting estrous cycles during anestrus. This study investigated the hypothesis that for a subpopulation of horse mares continuation of estrous cycles during the nonbreeding season may be attributed to continued stimulatory glutamatergic activity on GnRH-secreting neurons. The gonadotropin response to the glutamatergic agonist N-methyl-DL-aspartic acid (NMA) was compared in cycling and anestrous mares during the nonbreeding season. It was anticipated that the gonadotropin response to NMA in cycling mares would be attenuated, compared with that of anestrous mares. The experiment used 16 anestrous mares and 15 mares that cycled during ...
Membrane contact with oviductal epithelium modulates the intracellular calcium concentration of equine spermatozoa in vitro. Interaction of equine spermatozoa with oviductal epithelial cells (OEC) prolongs sperm viability and maintains low intracellular calcium concentration ([Ca2+]i) in spermatozoa. Experiments were designed to investigate 1) whether release of spermatozoa from OEC in vitro is associated with elevated [Ca2+]i and 2) whether soluble products from OEC or direct membrane contact between spermatozoa and OEC mediates the effects of OEC on sperm [Ca2+]i. In the first experiment, changes in [Ca2+]i in spermatozoa loaded with indo-1 acetoxymethylester were determined in motile spermatozoa released from OEC...
Differential transcription of steroidogenic enzymes in the equine primary corpus luteum during diestrus and early pregnancy. In pregnant mares, eCG stimulates luteal androgen and estrogen production, increasing plasma concentrations 2- to 3-fold. To study how these changes are regulated, we examined the expression of mRNA for the steroidogenic enzymes 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), cytochrome P450 17 alpha-hydroxylase/17,20-lyase (P450 17 alpha), and cytochrome P450 aromatase (P450arom) in equine primary corpora lutea using Northern blot analyses. Three equine specific cDNAs were generated by reverse transcriptase polymerase chain reaction. When compared to human, bovine, and rat sequences, the nu...
Antibody directed against plasma membrane components of equine spermatozoa inhibits adhesion of spermatozoa to oviduct epithelial cells in vitro. Before fertilization, equine spermatozoa adhere to oviduct epithelial cells (OEC) of the mare. The biochemical basis for this adhesion has not been determined. Our objective was to produce an antiserum to block this interaction. Ejaculated spermatozoa were subjected to nitrogen cavitation and spermatozoal plasma membranes enriched by sucrose density gradient centrifugation; membrane enrichment was confirmed by comparative alkaline phosphatase analysis, electron microscopy, and one- and two-dimensional PAGE. Periacrosomal plasma membrane was used as an immunogen for the production of an antiser...
A developmental switch in expression from blastocyst to endometrial/placental-type cytochrome P450 aromatase genes in the pig and horse. Pig blastocysts exhibit a transient period of estrogen production at periimplantation, with a second, more sustained period of estrogen synthesis occurring in endometrium and placenta at later pregnancy. Previously we reported the isolation of cDNA clones encoding a novel isoform of cytochrome P450 aromatase (the terminal enzyme in the estrogen biosynthetic pathway) from porcine periimplantation blastocysts. The present study investigated pregnancy-associated expression, in blastocysts and maternal reproductive tract tissues of this and an additional mRNA transcript encoding a distinct P450 ar...
Nucleologenesis and ribonucleic acid synthesis in preimplantation equine embryos. The nucleolus is believed to be the active site of rRNA synthesis in all eukaryotic cells. In preimplantation embryos, the embryonic genome is apparently more or less silent up to a species-specific developmental stage at which a major burst of transcription occurs. Here we report on nucleologenesis and some ultrastructural aspects of the onset of RNA synthesis in equine embryos during in vivo development. The zygotes and embryos up to blastocyst stages were surgically recovered from normally cycling mares. Mares were induced to ovulate by treatment with 3000 IU hCG and inseminated 20 and 34 h...
Intracellular calcium concentration in equine spermatozoa attached to oviductal epithelial cells in vitro. Interaction of spermatozoa with oviductal epithelial cells (OEC) in the oviductal isthmus prolongs the life span of spermatozoa. The hypothesis that the interaction of equine spermatozoa with OEC affects their intracellular calcium concentration ([Ca2+]i) was tested in a sperm-OEC coculture model. Changes in [Ca2+]i in spermatozoa loaded with the fluorescent calcium indicator indo-1 acetoxymethylester (AM) were determined for spermatozoa attached to OEC or to Matrigel, as well as for free-swimming spermatozoa incubated without oviductal epithelium. [Ca2+]i was determined before incubation and ...
Expression of major histocompatibility complex antigen and timing of invasion by equine chorionic girdle cells cultured on Matrigel. Chorionic girdle cells are a highly invasive subpopulation of trophoblastic cells of the horse conceptus that adhere to the uterine epithelium and begin to invade the endometrium on Days 34-36 (Day 0 = day of ovulation). Just prior to and during invasion (Days 32-36), chorionic girdle cells express high levels of major histocompatibility complex (MHC) I, but expression of this antigen decreases by Days 40-45 and is lost by Day 55. The mechanisms involved in the control of chorionic girdle cell invasion and altered MHCI expression over time are not known. The objective of this study, therefore,...
Demonstration of tissue-specific promoters in nonprimate species that express aromatase P450 in placentae. Conversion of androgens to estrogens is catalyzed by aromatase P450 (P450arom; the product of the CYP19 gene). Regulation of tissue-specific expression of P450arom in humans is due, in part, to alternative transcriptional start sites that arise as a consequence of the use of granulosa cells and placental tissue from cows, horses, and pigs (ungulates) in order to determine whether these species, like the human, utilize tissue-specific promoters to drive P450arom expression. The majority of transcripts in the placenta have 5'-termini that differ from those in the ovary upstream of a common site ...
Metalloproteinase activity has a role in equine chorionic girdle cell invasion. Chorionic girdle cells are a highly invasive subpopulation of trophoblast cells of the equine conceptus. By Day 35 (Day 0 = day of ovulation), cells of the chorionic girdle adhere to the uterine epithelium and begin to invade the endometrial wall. Invasive cells must attach to extracellular matrix proteins, secrete proteinases capable of degrading matrix, and migrate through the degraded matrix; invasion is largely dependent on the proteinase activity of the cells. The objective, therefore, was to develop an in vitro system to examine the mechanisms of equine chorionic girdle cell invasion thr...
Pulsatile gonadotropin secretion determined by frequent sampling from the intercavernous sinus of the mare: possible modulatory role of progesterone during luteolysis. Twelve horse mares were used in a repeated-measures design consisting of 3 replicates of 4 mares each. On Day 6 following ovulation, luteolysis was initiated with an i.m. injection of prostaglandin F2 alpha (PGF2 alpha; Lutalyse, 10 mg). Either 12 (-12) or 36 (-36) h before PGF2 alpha (PRE), blood samples were collected simultaneously from the intercavernous sinus (ICS) and jugular (JUG) vein at 10-min intervals for an 8-h period. Pituitary capacity to exogenous GnRH (2 micrograms/kg BW, i.v.) was evaluated at the alternate time point within this period. Frequent sampling and GnRH challenge we...