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Biomedical subjects

F W Bazer

Publications and source records attributed to F W Bazer.

At least 109 records · Page 6Linked to original sources
PubMed1995

Sulfated glycoprotein-1 (SGP-1) expression in ovine endometrium during the oestrous cycle and early pregnancy.

This study determined effects of day of oestrous cycle and early pregnancy on sulfated glycoprotein-1 (SGP-1) expression in ovine endometrium. A 364-bp clone of the ovine SGP-1 mRNA was amplified from reverse transcribed Day-15 cyclic endometrial mRNA using the polymerase chain reaction (PCR) and primers specific for the rat SGP-1 mRNA sequence. Nucleotide sequence of the ovine SGP-1 cDNA shared significant identity with rat SGP-1 and human prosaposin. Ewes (n = 40) were hysterectomized on either Day 1, 6, 11, 13 or 15 of the oestrous cycle or on Day 11, 13, 15, 17 or 25 of early pregnancy. Total cellular RNA was isolated from endometrium and subjected to Northern and slot blot hybridization analyses using an antisense cRNA probe transcribed from the ovine SGP-1 cDNA clone. A single 2.6-kb mRNA transcript was detected by Northern hybridization analyses. Slot blot hybridization analyses indicated that steady-state levels of endometrial SGP-1 mRNA varied during the oestrous cycle (cubic, P < 0.02) and increased between Day 11 and Day 25 of early pregnancy (linear, P < 0.01). On Days 11, 13 and 15, endometrial SGP-1 mRNA levels were greater in pregnant ewes than in cyclic ewes (day x pregnancy status, P < 0.01). Immunohistochemical localization of SGP-1 in uterine tissues with rabbit anti-rat SGP-1 antibody revealed intense immunoreactivity associated primarily with the endometrial epithelium. These results indicate that the ovine endometrium expresses SGP-1, a prosaposin, and that SGP-1 expression varies during the oestrous cycle and is enhanced by the conceptus. The presence of SGP-1 in the endometrium suggests intracellular and extracellular roles for this protein in glycosphingolipid metabolism or transport in the uterine environment.

Animals↗
PubMed1995

Developmental changes of free amino acid concentrations in fetal fluids of pigs.

Free amino acid concentrations were determined in amniotic and allantoic fluids and in fetal and maternal uterine plasma of pigs during gestation. Glycine and glutamine were the most abundant free amino acids in maternal uterine arterial and fetal umbilical venous plasma, respectively. Plasma fetal/maternal ratios were remarkably < 1 for glycine, > 2 for glutamine and = 1 for total free alpha-amino acids. Glutamine was the most abundant free amino acid in amniotic fluid during the first 3 mo of gestation. The concentrations of most amniotic fluid amino acids progressively decreased with increasing gestational age from 45 to 110 d. Glycine was the most predominant amino acid in allantoic fluid on d 30 of gestation but decreased on d 45 and 60 of gestation. This decrease in allantoic fluid glycine coincided with a marked increase in concentrations of both ornithine and arginine, which accounted for 34-36% of total free alpha-amino acids in allantoic fluid. Such an abundance of ornithine and arginine in allantoic fluid has not been reported for any other biological fluid. On d 90 and 110 of gestation, glycine again became the most abundant amino acid in allantoic fluid, or 47 and 29% of total free alpha-amino acids, respectively. Urea concentrations in amniotic and allantoic fluids progressively increased during the second half of pregnancy, indicating enhanced fetal protein metabolism. Our results demonstrate the abundance of glutamine in fetal plasma, the unusual abundance of ornithine, arginine and glycine in allantoic fluid and developmental changes in plasma fetal/maternal ratios of amino acids.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1995

Colony-stimulating factor-1 in conceptus and uterine tissues in pigs.

Colony-stimulating factor-1 (CSF-1), a growth factor for cells of monocyte/macrophage lineages, is produced by uterine and placental tissues in humans and mice and may stimulate placental growth and development. The present study characterized CSF-1 mRNA and protein expressed by porcine uterine, conceptus, allantochorion, and fetal tissues at various stages of pregnancy. A human CSF-1 cDNA and an anti-human CSF-1 monoclonal antibody were utilized to examine CSF-1 mRNA and protein. Northern blot analyses detected mRNA transcripts of 3.6-5.1 kb in pig tissues. A 4.0-kb transcript was common to all tissues examined. Endometrial CSF-1 mRNA increased (p < 0.05) as pregnancy proceeded, with highest levels at term, and was temporally associated with concentrations of estrogen (E) in plasma. Placental expression of the CSF-1 gene increased (p < 0.05) throughout gestation with the major increase occurring between Days 20 and 30, after which time high levels of mRNA were maintained to term. The changes in placental CSF-1 mRNA were temporally associated with periods of rapid placental and fetal growth. High levels of CSF-1 mRNA were also detected in skeletal muscle, kidney, and intestine of fetuses. Immunoreactive CSF-1 was detected in all of the tissues examined. Partial cloning of the porcine CSF-1 gene indicated greater than 98% identity with the human CSF-1 gene. CSF-1 gene expression in endometrium was not affected by exogenous E or progesterone treatment in ovariectomized gilts. These results suggest that CSF-1 may influence placental and fetal growth, and its differential expression in fetal tissues indicates that CSF-1 may also affect embryonic differentiation and growth of those tissues.

Animals↗
PubMed1995

Ovine interferon-tau regulates expression of endometrial receptors for estrogen and oxytocin but not progesterone.

Ovine interferon-tau (oIFN-tau) may stabilize endometrial progesterone receptor (PR) and/or inhibit estrogen receptor (ER) gene expression during pregnancy recognition to suppress endometrial oxytocin receptor (OTR) formation and production of luteolytic prostaglandin (PG) F2 alpha pulses. This study determined whether or not oIFN-tau stabilized PR expression in the endometrium during PR down-regulation by continuous exposure to progesterone. Twenty cyclic ewes were bilaterally ovariectomized and fitted with uterine catheters on Day 2 of the estrous cycle (Day 0 = estrus). Ewes were then assigned randomly to be treated, in a 2 x 2 factorial arrangement, with recombinant oIFN-tau (roIFN-tau; 2 x 10(7) antiviral units per ewe per day) or control proteins (6 mg/day) by intrauterine injection from Days 10 to 14, and with daily i.m. injections of 20 mg progesterone from Days 2 to 14 (P) or progesterone from Days 2 to 14 plus 50 micrograms estradiol-17 beta from Days 12 to 14 (P+E). All ewes were hysterectomized on Day 15. Endometrial PR mRNA (p < 0.01) and protein (p < 0.03) were higher in ewes receiving P+E than in those receiving P alone. However, the increase in PR mRNA and protein was not as great in the endometrium of roIFN-tau-treated ewes as compared to controls (p < 0.08, treatment x steroid). In ewes receiving P alone, PR mRNA and immunoreactive PR were localized to stroma and deep glandular epithelium and were not present in endometrial luminal and shallow glandular epithelium. Values for endometrial ER mRNA (p < 0.02) and ER protein (p < 0.01) were greater in controls than in roIFN-tau-treated ewes regardless of steroid treatment. Among controls, ER mRNA and immunoreactive ER protein were present in the luminal and glandular epithelium and were increased in the epithelium and stroma in ewes receiving estrogen. In contrast, endometrial ER mRNA and immunoreactive ER protein were very low or absent in the endometrium of roIFN-tau-treated ewes and were not increased by estrogen. Among controls, endometrial OTR density was greater (p < 0.09) in ewes treated with P+E than in those treated with P alone. In roIFN-tau-treated ewes, endometrial OTR density was lower (p < 0.01) than in the controls. Results indicate that roIFN-tau did not stabilize or prevent autologous down-regulation of PR mRNA or protein expression in the endometrium. However, roIFN-tau did suppress endometrial ER expression and OTR formation in ewes regardless of steroid treatment. The results support the hypothesis that the antiluteolytic effects of oIFN-tau are to suppress endometrial ER gene expression in the endometrial epithelium, thereby inhibiting formation of OTR and production of luteolytic PGF2 alpha pulses.

Animals↗
PubMed1995

Temporal and spatial alterations in uterine estrogen receptor and progesterone receptor gene expression during the estrous cycle and early pregnancy in the ewe.

Mechanisms regulating responses of the ovine uterus to endocrine and paracrine signals during the estrous cycle and pregnancy are likely to require tissue- and cell-specific regulation of steroid hormone receptor gene expression. To determine effects of day and pregnancy status (cyclic or pregnant) on uterine estrogen receptor (ER) and progesterone receptor (PR) gene expression, ewes were hysterectomized either on Day 1 (Day 0 = estrus/mating), 6, 11, 13, or 15 of the estrous cycle (n = 3/day) or on Day 11, 13, 15, 17, or 25 of early pregnancy (n = 5/day). Steady state levels of ER and PR mRNA were determined in endometrial and myometrial tissues by slot-blot hybridization and ribonuclease protection assays, respectively, using homologous ovine ER and PR cRNA probes. Changes in spatial expression of ER and PR mRNA and protein in uterine tissue sections were determined by in situ hybridization and immunocytochemical analyses. In cyclic ewes, steady state levels of endometrial ER mRNA were highest on Day 1, declined between Days 1 and 6, and increased between Days 11 and 15. However in pregnant ewes, endometrial ER mRNA levels decreased between Days 11 and 15 and increased slightly between Days 15 and 25. In cyclic ewes, levels of myometrial ER mRNA were highest on Day 1, decreased to Day 6, and remained low thereafter. In cyclic ewes, endometrial PR mRNA levels were highest on Day 1, decreased between Days 1 and 11, and then increased between Days 13 and 15. In cyclic ewes, myometrial PR mRNA levels were highest on Day 1 and declined thereafter. Endometrial PR mRNA levels were not different between cyclic and pregnant ewes on Days 11, 13, and 15. In pregnant ewes, PR mRNA levels were low on Day 11, increased between Days 11 and 17, and decreased between Days 17 and 25. In pregnant ewes, myometrial PR mRNA levels were low and did not change between Days 11 and 25. In situ hybridization and immunocytochemical analyses revealed distinct tissue- and cell type-specific alterations in uterine ER and PR mRNA and protein expression during the estrous cycle and early pregnancy that generally paralleled overall changes in steady state levels of ER and PR mRNAs. In the endometrium, the most striking observation was that PR mRNA and protein expression disappeared from the luminal and shallow glandular epithelium between Days 6 and 13 of the estrous cycle, whereas ER mRNA and protein expression was low on Days 6 and 11 and increased between Days 11 and 15 in the luminal and shallow glandular epithelium. During early pregnancy, expression of ER and PR mRNAs, as well as ER and PR protein, was very low or absent in the luminal and shallow glandular epithelium between Days 13 and 25 of pregnancy. Moreover, ER and PR mRNA and protein were consistently present at low levels in the stroma and deep glandular epithelium in both cyclic (Days 11-15) and pregnant (Days 11-25) ewes. Collectively, results suggest that uterine ER and PR gene expression is regulated in a tissue- and cell type-specific manner during the estrous cycle and early pregnancy.

Animals↗
PubMed1995

Ovine interferon-tau inhibits estrogen receptor up-regulation and estrogen-induced luteolysis in cyclic ewes.

This study determined whether intrauterine injection of interferon-tau (IFN tau) could block luteolysis in cyclic ewes treated with a luteolytic dose of 17 beta-estradiol benzoate (E) on day 12 of the estrous cycle. Thirty-two ewes were fitted with uterine catheters on day 5 of the estrous cycle and treated with recombinant ovine IFN tau (2 x 10(7) antiviral units/ewe/day) or control proteins (6 mg/day) by intrauterine injection from day 10 until hysterectomy. At 1900 h on day 12, all ewes received 750 micrograms E, im, and were hysterectomized 12, 24, 36, or 48 h post-E administration. Plasma concentrations of progesterone declined in control animals but increased in IFN tau-treated ewes after E injection (P < 0.01, treatment x day interaction). Likewise, total corpus luteum weight decreased in control but not IFN tau-treated ewes after E administration (P < 0.02, treatment x time interaction). In control ewes, endometrial estrogen receptor (ER) messenger RNA (mRNA; P < 0.03) and progesterone receptor (PR) mRNA (P < 0.10) increased after 12 h, whereas concentrations of ER protein (P < 0.02) and PR protein (P < 0.04) increased after 24 h. In situ hybridization and immunohistochemical analyses indicated that ER gene expression increased first in the epithelium at 12 h and then in the stroma by 48 h, whereas PR gene expression first increased in the stroma and then in the epithelium. In control ewes, endometrial oxytocin receptor (OTR) density increased (P < 0.10) after 12 h, with the largest increase occurring between 36-48 h. In IFN tau-treated ewes, endometrial ER mRNA and protein and OTR density did not increase after E administration. Levels of PR mRNA increased (P < 0.01) between 12-36 h, but decreased after 36 h. PR mRNA abundance increased between 12-36 h in the stroma, but not in the epithelium. Concentrations of PR protein were low and did not change in IFN tau-treated ewes. Immunoreactive PR protein was present at low levels in the stroma of all IFN tau-treated ewes. The results indicate that induction of luteolysis by E in control ewes involved sequential increases in endometrial ER mRNA and ER protein in the epithelium that preceded maximal increases in OTR density. Intrauterine injection of recombinant ovine IFN tau prevented luteolysis by inhibiting estrogen-induced increases in endometrial ER and OTR gene expression.

Animals↗
PubMed1995

Extension of corpus luteum lifespan and reduction of uterine secretion of prostaglandin F2 alpha of cows in response to recombinant interferon-tau.

Two experiments tested the effect of recombinant ovine and bovine interferon-tau on corpus luteum lifespan, interestrous interval, and oxytocin-induced uterine secretion of prostaglandin F2 alpha. Cows received intrauterine injections of 100 micrograms of recombinant ovine interferon-tau plus 1.4 mg of BSA or of 1.5 mg of BSA alone in Experiment 1 and 200 micrograms of recombinant bovine interferon-tau plus 1.3 mg of BSA or 1.5 mg of BSA alone in Experiment 2. Twice daily injections (0700 and 1900 h) were split evenly between the uterine horns from d 14 to 24 of the experimental estrous cycle via an AI pipette in Experiment 1 and via intrauterine catheters in Experiment 2. On d 17, cows were injected with 100 IU of oxytocin, and plasma was collected for analysis of 13,14-dihydro-15-keto-prostaglandinF2 alpha. Recombinant ovine interferon-tau extended the lifespan of the corpus luteum (27.5 vs. 19.2 d) and interestrous interval (30.5 vs. 20.6 d) and abolished the oxytocin-induced increase in 13,14-dihydro-15-keto-prostaglandinF2 alpha, which peaked at 30 min for the BSA control group (210.8 pg/ml). Recombinant bovine interferon-tau also extended the lifespan of the corpus luteum (29.0 vs. 21.4 d) and interestrous interval (31.5 vs. 22.6 d) and abolished the oxytocin-induced increase in 13,14-dihydro-15-keto-prostaglandin F2 alpha, which peaked at 30 min for the BSA control group (205.6 pg/ml). In conclusion, recombinant ovine interferon-tau and recombinant bovine interferon-tau were effective antiluteolytic agents in cattle.

Animals↗
PubMed1994

Porcine conceptus and endometrial retinoid-binding proteins.

Porcine conceptus secretory proteins were obtained from medium in which pig conceptuses, collected on Day 15 of pregnancy, were cultured for 30 h. Culture medium was pooled, dialysed and concentrated by Amicon ultrafiltration for retinol and retinoic acid (RA) binding studies. Proteins in the 20-kDa range, conceptus-secreted retinol-binding protein (RBP), bound both [3H]retinol and [3H]RA specifically. Cross-competition experiments indicate that [3H]RA was completely displaced with excess cold retinol; however, excess cold RA did not completely displace [3H]retinol, suggesting that conceptus RBP has greater affinity for retinol than RA. Cellular RBP and retinoic acid receptor (RAR)-alpha and RAR-gamma mRNA transcripts (0.7 kb; 3.8 and 2.8 kb; 3.4 kb respectively) were detected in poly (A)+ RNA isolated from Day-15 conceptus, Day-15 pregnant endometrium, late pregnant myometrium and late pregnant fetal tissues of pigs by Northern blot analysis. RAR-alpha and RAR-gamma immunoreactive proteins were detected in extracts of Day-15 conceptus, Day-15 pregnant endometrium and late pregnant fetal tissues by Western blot analysis. Collectively, results indicate that biochemical molecules required for retinoid transport, metabolism and regulatory effects are present in porcine conceptus and endometrial tissues during early pregnancy in swine.

Animals↗
PubMed1994

Immunocytochemical localization and changes in endometrial progestin receptor protein during the porcine oestrous cycle and early pregnancy.

Changes of progesterone receptor (PR) protein and cellular localization in the endometrium were evaluated during the oestrous cycle and early pregnancy of the gilt. During the oestrous cycle, the concentration of total PR protein within the endometrium was highest on Days 0-5 and decreased on Day 10. The endometrial concentration of PR reached a nadir on Day 12 and this level was maintained throughout the remainder of the oestrous cycle (Day 18). In pregnant gilts, the concentration of endometrial PR protein from Day 10 to Day 18 was similar to that in cyclic gilts. Western blot analysis with antiserum specific for the A and B isoforms of PR indicated that porcine endometrium expresses both isoforms of PR. Immunostaining was detectable for both the A and B isoforms of PR from Day 0 to Day 12 of the oestrous cycle. However, no staining was observed on Day 15 and Day 18 of the oestrous cycle or pregnancy Immunocytochemical localization of PR in the endometrium of cyclic gilts and pregnant gilts indicated that there was intense staining for PR in surface epithelium and glandular epithelium during oestrus (Day 0) and on Day 5. However, the staining was less intense on Day 7 and Day 10 of the oestrous cycle and no epithelial staining was observed after Day 12. PRs were present in the stroma and myometrium throughout the oestrous cycle and early pregnancy. The presence of conceptuses during pregnancy did not affect the loss of PR from the uterine epithelium after Day 10 of gestation. Down-regulation of epithelial PR might be one factor involved in the timing of luteolysis during the oestrous cycle as well as conceptus growth and placentation during early pregnancy.

Animals↗
PubMed1994

Structure/function studies with interferon tau: evidence for multiple active sites.

A novel interferon (IFN), called IFN-tau (IFN-tau), has recently been discovered and has been shown to be a pregnancy recognition hormone. Unlike known IFNs, however, IFN-tau exhibits high antiviral and antiproliferative activity without cytotoxicity. The structural basis for IFN-tau function has been examined using six overlapping synthetic peptides corresponding to the entire ovine (Ov) IFN-tau sequence. Four peptides representing amino acids 1-37, 62-92, 119-150, and 139-172 inhibited OvIFN-tau antiviral activity in a dose-dependent manner. Polyclonal antipeptide antisera directed against the same four peptides blocked OvIFN-tau binding and antiviral activity, confirming the specificity of the peptide competitions. Because IFN-tau and IFN-alpha both interact with the type I IFN receptor, peptide inhibition of bovine and human IFN alpha activity was also determined. Of importance, only three peptides, OvIFN-tau (62-92), (119-150), and (139-172) inhibited IFN-alpha antiviral activity. The amino-terminal IFN-tau peptide, OvIFN-tau(1-37), was not inhibitory. These data suggest that the internal and carboxy-terminal reactive domains of IFN-tau may interact with a common type I IFN site on the receptor, while the amino terminus interacts with a site that elicits activity unique to OvIFN-tau. Finally, the antiproliferative activity of OvIFN-tau was localized primarily to the broad carboxy-terminal region, with OvIFN-tau(119-150) being the most effective inhibitor of OvIFN-tau-induced reduction of cell proliferation. Thus, multiple domains of IFN-tau have functional significance.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

Predicted structural motif of IFN tau.

Ovine interferon tau (IFN tau) is a type I interferon that was originally identified as ovine trophoblast protein and is associated with the maternal recognition of pregnancy in sheep. Additionally, IFN tau possesses potent antiviral and antiproliferative activity without the corresponding toxicity found in known IFN alpha s. Structure-function studies with synthetic peptides have identified three discontinuous functional sites on the protein that are involved in receptor interaction and biological activity. However, the structural relationship of these regions is unknown. Therefore, a model relationship of these regions is unknown. Therefore, a model of the 3-D structure of IFN tau would be useful in interpretation of existing data and the design of future structure-function studies. Combining information from circular dichroism (CD) of both the full length recombinant IFN tau and synthetic peptides representing regions of the IFN tau molecule, with sequence homology of IFN tau to IFN beta, a protein of known 3-D structure, we have constructed a model of IFN tau using distance geometry and energy minimization methods. The most striking feature of this model is that functionally active domains of IFN tau, discontinuous in the primary structure, are localized to one side of the molecule and found to be spatially contiguous. This observation is consistent with multiple binding sites on IFN tau interacting simultaneously with the IFN tau receptor.

Amino Acid Sequence↗
PubMed1994

Retinol-binding protein: immunolocalization of protein and abundance of messenger ribonucleic acid in conceptus and maternal tissues during pregnancy in pigs.

Retinol-binding protein (RBP) is a major secretory product of liver as well as uterine endometrium and periimplantation conceptuses of pigs. The present study examined distribution of RBP protein and abundance of RBP mRNA in pig maternal and conceptus tissues throughout pregnancy. A porcine liver RBP cDNA clone was isolated and used as probe in these studies. Northern blot analysis detected a 1.0-1.1-kb transcript in conceptus, trophoblast, yolk sac, placenta, endometrium, myometrium, oviduct, and numerous fetal tissues. Slot blot analyses of RBP mRNA abundance in endometrium, myometrium, conceptus, trophoblast, chorioallantoic placenta, and embryo/fetus indicated differential RBP gene expression in each tissue. Immunocytochemical localization studies indicated the presence of immunoreactive RBP in endometrial surface and glandular epithelium, circular and longitudinal muscle of myometrium, parenchymal cells of fetal liver, and proximal convoluted tubules of fetal kidney. Results suggest an integrated system of RBP gene expression and protein secretion that allows for transport of retinol from the uterine endometrium to the periimplantation conceptus during early pregnancy and to the fetal-placental unit throughout pregnancy in pigs.

Allantois↗
PubMed1994

Effects of administration of human chorionic gonadotropin or progesterone before maternal recognition of pregnancy on blastocyst development and pregnancy in sheep.

A series of four experiments with 258 ewes was conducted to determine whether blastocyst size could be altered before normal luteolysis and, if so, how this affected fertility. In Exp. 1 and 2, nonmated and mated ewes, respectively, were treated with hCG (100 IU), progesterone (12 mg), or vehicle on d 11.5 (d 0 = onset of estrus). In Exp. 3 and 4, field trials were conducted to compare the effects of either hCG or progesterone treatment on d 11.5 on subsequent pregnancy rates. In Exp. 1, hCG transiently increased (P < .01) concentrations of progesterone and estradiol in plasma, whereas progesterone treatment increased only plasma progesterone. Neither hCG nor progesterone affected the duration of the estrous cycle. In Exp. 2, d-13 blastocysts were longer (3.5 +/- 1.6 vs .8 +/- .5 cm; Mean +/- SE; P < .05), and concentrations of protein and interferon tau (IFN tau) in uterine flushings were greater (10.7 vs 1.2 micrograms; P < .05) in hCG than in vehicle-treated ewes. Progesterone treatment did not affect blastocyst development. In Exp. 3, pregnancy rates tended to be greater (P < .10) in ewes given hCG than in those given vehicle (44/47; 94% vs 40/48; 83%); however, administration of progesterone in Exp. 4 had no effect on pregnancy rates (P < .14; 41/45; 91% vs 37/46; 80%; control ewes). These results indicate that treatment with hCG on d 11.5 stimulated uterine secretions and conceptus growth sufficiently to influence pregnancy rates.

Animals↗
PubMed1993

Intrauterine injection of recombinant ovine interferon-tau extends the interestrous interval in sheep.

The ability of recombinant ovine interferon-tau (roIFNtau) to extend the interestrous interval (IEI) in sheep was studied. Ewes were fitted with bilateral uterine catheters 7 or 8 days post estrus and were assigned to receive either 10 or 20 million antiviral (AV) units/day i.u. ( approximately 100 or 200 ug) of roIFNtau or ovine conceptus secretory proteins containing equivalent AV units of native oIFNtau (noIFNtau; 4 ewes/treatment). Four control ewes received ovine serum proteins (SP). Total protein injected was 6 mg per day, half at 0700 hours and half at 1730 hours. The treatments were administered from Day 11.5 (estrus=Day 0) to Day 16. Blood samples were collected by jugular vienipuncture daily from Day 11 until ewes returned to estrus. Concentrations of progesterone (P) in plasma were determined by RIA. Treatment with either noIFNtau or roIFNtau extended IEI beyond that of SP-treated ewes (19.1 vs 31.2+/-3.4 days P<0.03). Of the ewes receiving 100 mug/day of oIFNtau, 2 of 4 receiving noIFNtau (23.6+/-5.2 days) and 3 of 4 receiving roIFNtau (34.2+/-5.2 days) had an extended IEI. All ewes receiving 200 mug/day of noIFNtau or roIFNtau had an extended IEI (28.8 and 38.5+/-5.2 days. respectively). Ewes receiving roIFNtau had a longer IEI than those receiving noIFNtau (36.7 vs 26.2+/-3.4 days; P=0.07). Ewes with an extended IEI had functional corpora lutea, as assessed by P production. The results demonstrate that 10 or 20 million AV units ( approximately 100 or 200 ug) of roIFNtau extends the IEI and that the length of the IEI is longer for ewes receiving roIFNtau than noIFNtau following injection of equivalent AV units.

Journal Article↗
PubMed1993

Changes in oestrogen receptor protein, mRNA expression and localization in the endometrium of cyclic and pregnant gilts.

Conceptus secretion of oestrogen on Day 11 of gestation is involved with establishment of pregnancy in the pig. Changes in oestrogen receptor (ER) protein, mRNA and cellular localization in the endometrium were evaluated during the oestrous cycle and early pregnancy of the gilt. In nonpregnant gilts, concentration of nuclear ER in the endometrium increased from Days 0 to 12 followed by a decline on Day 15 of the oestrous cycle. In pregnant gilts, changes in endometrial nuclear ER during Days 10, 12, 15 and 18 were similar to that in cyclic pigs. Analysis of endometrial ER mRNA expression did not detect any difference between cyclic and pregnant pigs between Days 10 and 15 postoestrus. Expression of ER mRNA in endometrium of cyclic and pregnant gilts was greatest on Day 10 followed by a decline on Day 15. Endometrial ER mRNA increased on Day 18 of the oestrous cycle, but remained low during pregnancy. Immunocytochemical localization of ER in the endometria of cyclic and pregnant gilts indicated that there was intense staining for ER in stromal cells and moderate to strong staining in surface and glandular epithelial cells during oestrus (Day 0) and Day 18 of the oestrous cycle. However, stromal ER staining was absent from Days 5 to 15 of the oestrous cycle and continued to be suppressed on Day 18 of pregnancy. Immunocytochemical staining of ER in the surface and glandular epithelium was readily detectable from Days 0 to 12 of the oestrous cycle and during pregnancy. Intensity of staining for ER declined in surface epithelial cells on Day 15 in both cyclic and pregnant pigs whereas positive staining for ER in glandular epithelium was absent. Staining for ER on uterine surface epithelial cells increased during pro-estrus (Day 18) of cyclic gilts but remained similar to Day 15 in pregnant gilts. Changes in endometrial ER protein, mRNA and localization in surface epithelium are consistent with a physiological role for conceptus oestrogen secretion in uterine function and maternal recognition of pregnancy in the pig.

Animals↗
PubMed1993

Determination of porcine endometrial phospholipase A2 activity and detection of immunoreactive cyclooxygenase during the oestrous cycle and early pregnancy.

Experiments examined the characteristics and activity of phospholipase A2 (PLA2) and examined the presence of immunoreactive cyclooxygenase in endometrium of pigs during the oestrous cycle and early pregnancy. Endometrial PLA2 was calcium-independent and activity of the enzyme was greatest at a pH of 8.0. Activity of PLA2 on Days 10, 12, 14 and 16 of the oestrous cycle did not differ (P > 0.1) from activity on those days during pregnancy. During oestrus and early metoestrus (Days 0-3), cyclooxygenase was present in both glandular and surface epithelium. After Day 10 of the oestrous cycle or pregnancy, staining for cyclooxygenase was less intense in the lower and middle uterine glands. However, the upper glandular epithelium near the surface epithelium stained intensely. By Day 15 of the oestrous cycle or pregnancy, intense staining for cyclooxygenase appeared restricted to the upper uterine glands. These results indicate changes in localization of immunoreactive cyclooxygenase throughout the oestrous cycle and suggest that these are not related to altered secretion of prostaglandins (PGs) during early pregnancy. The stimulatory effects of porcine conceptus products on secretion of PGs during early pregnancy are apparently not associated with increased activity of endometrial PLA2.

Animals↗
PubMed1993

Retinol-binding protein gene expression in cyclic and pregnant endometrium of pigs, sheep, and cattle.

Retinol-binding protein (RBP) is a major secretory product of conceptuses and endometrium of the large domestic animals. The present study examined the abundance of RBP mRNA in cyclic and early pregnant endometrium of pigs, sheep, and cattle and confirmed the presence of RBP mRNA in preiimplantation conceptuses of the large domestic animals. Northern blot analysis, using porcine liver RBP cDNA as the probe, detected a 1.0-1.1-kb transcript in conceptuses and endometrium collected during the preiimplantation period of pregnancy in pigs (Day 15), sheep (Day 16), and cows (Day 18). Slot-blot analysis of RBP mRNA in endometrium of pigs, sheep, and cows indicated differential RBP gene expression across days and statuses in pigs and sheep and across days alone in cows. In pigs, RBP gene expression was low to undetectable at Days 0, 5, and 10 of the estrous cycle and Day 10 of pregnancy. Levels of RBP mRNA increased (p < 0.06) from Days 10 to 12 and further (p < 0.001) to Day 15 across both statuses. At Day 18, RBP mRNA levels decreased (p < 0.01) in cyclic pigs but remained elevated in endometrium of pregnant pigs. In sheep, levels of RBP mRNA increased between Days 10 and 12 and 14 in both cyclic and pregnant ewes; however, between Days 14 and 16, RBP mRNA levels remained elevated in cyclic endometrium but decreased (p < 0.01) in endometrium of pregnant ewes. In a second experiment, RBP mRNA levels increased (p < 0.01) between Days 0-5 and Days 13-15 of the estrous cycle.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗