Immunosuppressive activity associated with early pregnancy in the bovine

Immunosuppressive activity was assessed in uterine flushings (UF) and uterine vein serum and plasma from nonpregnant and early-pregnant cows, and in media from the short-term culture of Day 18 bovine embryos. The preparations were tested for their ability to inhibit [3H] thymidine (3H-TdR) incorporation into phytohemagglutinin-stimulated bovine lymphocytes. On Days 2-3 (called Day 3), Days 9-10 (called Day 10), and Days 17-19 (called Day 18) of the estrous cycle (estrus = Day 0) and pregnancy, untreated and superovulated cows were anesthesized and jugular vein and uterine vein blood was collected. The uteri were removed and flushed to obtain UF and embryos. Uterine flushings were concentrated and tested for immunosuppressive activity at 400 micrograms uterine protein/ml culture fluid. Uterine flushings from both Day 18 pregnant and Day 18 nonpregnant cows were immunosuppressive (8/8), whereas Day 10 UF were usually not immunosuppressive (7/10). Day 3 UF were usually stimulatory or only marginally suppressive (8/8). Uterine vein serum and plasma from Day 18 cows were not suppressive when compared to jugular vein serum or plasma from the same cow; neither were Day 18 uterine vein serum or plasma suppressive when compared to those same samples taken from Day 3 cows. Embryo culture media obtained from the 48-h culture of Day 18 embryos was consistently suppressive. The activity was lost after dialysis in 1000-Mr cut-off tubing, removed by charcoal, and reduced by protease digestion. These results suggest two mechanisms whereby the embryo could escape immune rejection: 1) the progesterone-induced secretion of a uterine immunosuppressive substance(s) and 2) the production by the embryo of a low molecular weight immunosuppressive substance(s).     

Influence of uterine flushings from superovulated cows on in vitro bovine morulae development

To evaluate early embryo development, 248 good to excellent bovine morulae were cultured in Ham's F-10 medium, supplemented with 10% steer serum, uterine flushings from Days 6, 10 or 15 following estrus (0.01, 0.1, 1.0 and 10% protein; 64 mg protein/ml), and 1.0% uterine flushings and 10% steer serum. Final development scores for embryos in steer serum were significantly higher (range across experiments was: 4.06 to 4.37) than for embryos cultured in uterine flushings alone (-0.23 to 0.52). Treatment means were not different (P >0.05) when 10% steer serum was added to 1.0% uterine flushings. A higher percentage of embryos in 10% steer serum (92%) than in 10% steer serum plus 1.0% uterine flushing from Day 6 (33%), Day 10 (45%) and Day 15 (50%) developed to hatched blastocysts. Embryos cultured in 1.0% Day 6 uterine flushings plus 10% steer serum required more time to attain the early blastocyst and blastocyst stages, while embryos in 1.0% Day 15 uterine flushings and 10% steer serum developed at the same rate as controls to the expanded blastocyst stage, but hatched sooner (72.8 vs 96.5 h). These results suggest substance(s) in uterine secretions can have inhibitory and stimulatory influences on early bovine embryo development.     

Ovulation and early embryogenesis in swine

Thirty gilts were used to examine if the sequence in which oocytes were released at ovulation contributed to differences in embryonic development and uterine secretions by Day 12 (Day 0 = onset of estrus). Oocytes of follicles destined to ovulate last were recovered 42 h after injecting proestrous gilts with hCG, incubated with a fluorescent stain, and returned to the donor's oviduct. These later-maturing oocytes subsequently became the lesser-developed (p less than 0.01) embryos on Day 4. In a second experiment, lesser- vs. more-developed Day 4 embryos from additional gilts were transferred to ligated uterine horns of nonpregnant gilts. Subsequently, the lesser-developed Day 4 embryos became the smaller (p less than 0.01) blastocysts within a litter on Day 12. Uterine flushings associated with lesser-developed embryos on Day 12 contained less estradiol (p less than 0.01), less total protein (p less than 0.10), and less acid phosphatase activity (p less than 0.05), but total content of calcium was not different compared to flushings that contained more-developed embryos. Analysis of uterine flushings with two-dimensional PAGE procedures indicated advanced uteroferrin-associated glycoprotein secretion from the horn that contained more-developed embryos. Results of these experiments suggested that oocytes of later-ovulating follicles were progenitors of smaller embryos, which probably stimulated uterine secretion later than more advanced littermates on Day 12.     

Secreted and placental membrane forms of folate-binding protein occur sequentially during pregnancy in swine

The objective was to understand how two forms of folate-binding protein interact to accomplish folate transport during pregnancy in swine. Specific folate binding was measured in uterine flushings during the estrous cycle and early pregnancy and in allantoic fluid (secreted form) and placental membranes (membrane form) throughout later pregnancy. In addition, the localization of the secreted form of folate-binding protein (sFBP) in uterine wall sections was assessed. Uterine flushings were collected on Days 10, 13, and 15 of the estrous cycle and pregnancy. Allantoic fluid and placentas were collected on Days 20, 35, 50, 70, 90, and 105 of pregnancy. Uterine-wall sections were collected on all days of the experiment. Folate binding was measured by incubation of aliquots of uterine flushings, allantoic fluid, or placental microsomal membranes with 0.5-4 nM [(3)H]folate. Uterine-wall sections were incubated with purified anti-FBP IgG or normal rabbit serum IgG to localize sFBP. Folate binding did not differ between early pregnancy and the estrous cycle in uterine flushings, was greatest from Day 50 to 70 of pregnancy in allantoic fluid, and was greatest from Day 50 of pregnancy onward in placental microsomal membranes. Staining for sFBP was present in the endometrial glands from Day 10 to 15 in cyclic gilts and from Day 10 to 20 in pregnant gilts. The pattern of folate binding and sFBP staining supports the concept that sFBP transports folate to the developing conceptus until placentation and then the placental form takes over folate transport.     

An investigation of the uterine luminal environment of non-pregnant and pregnant pony mares.

Uterine flushings were collected from 30 non-pregnant Pony mares on Days 8, 12, 14, 16, 18 or 20 after oculation. Mares were allowed a recovery period of one oestrous cycle and were mated at the next oestrus. They were then ovario-hysterectomized on days which corresponded to the day of the oestrous cycle to which they were assigned. Uterine flushings were analysed for total recoverable protein and acid phosphatase activity. Least squares analysis indicated a status X day interaction for total protein (P less than 0.10) and acid phosphatase activity (P less than 0.005) in which the latter was higher in uterine flushings during pregnancy. Peripheral plasma oestrone and oestradiol concentrations were measured by radioimmunoassay and results indicated that plasma oestrone concentrations in pregnant and non-pregnant mares were not different, and oestradiol was lower (P less then 0.005) in the peripheral plasma during pregnancy. conceptus membranes were incubated in vitro for 120 min in a chemically defined medium. Incubation medium was then assayed to assess oestrone and oestradiol production capacilities at Days 8, 12, 14, 16, 18 and 20 of pregnancy. Conceptus membrane production of oestradios (pg/5 ml/h) increased (P less than 0.05) from Day 8 (243 pg/5 ml) to Day 20 (108 763 pg/5 ml). A similar trend, but of lower magnitude, existed for oestrone production.     

The effects of superovulation on Brucella abortus infection in the bovine uterus

Uterine flushings were collected three times at predetermined intervals from 11 mixed-breed beef cows and cultured for Brucella abortus . Prior to sampling, all cows had aborted fetuses from which brucellae had been isolated. Initial collections were made between 21 and 34 days following abortion. The second flushing was conducted at the onset of injections used for inducing superovulation and the third flushing was conducted 6 to 8 days after the ensuing estrus. The latter two flushes were conducted between 60 and 120 days following abortion. Brucellae were isolated from uterine flushings collected from 6 of the 11 cows on the initial round of sampling. Cultures of all subsequent uterine flushings collected before and after injections for superovulation were negative. It was concluded that the superovulatory treatment is not likely to reactivate the release of brucellae into the uterine lumen during the period when embryos are normally collected.     

A study of prostaglandin F2α as the luteolysin in swine: V comparison of prostaglandin F, progestins, estrone and estradiol in uterine flushings from pregnant and nonpregnant gilts

Uterine flushings were collected from 38 gilts representing Days 6,8,10,12,14,15,16 and 18 of the estrous cycle and pregnancy. The same group of gilts were represented within each of the respective days of the estrous cycle and pregnancy, i.e., three to six gilts per day per status. Uterine flushings (about 40ml) were assayed for prostaglandin F (PGF), estrone (E₁), estradiol (E₂), progestins (P) and protein. Nonpregnant gilts had higher (P<.01) concentrations of P in uterine flushings than pregnant gilts, but pregnant gilts had higher (P<.01) E₁ and E₂ concentrations. Significant day by status interactions were detected for E₁ (P<.05), but not for E₂ concentrations in uterine flushings. Total recoverable PGF and PGF concentrations in uterine flushings were greater (P<.01) in pregnant than nonpregnant gilts and significant (P<.01) day by status interactions were detected. In nonpregnant gilts, PGF increased between Days 12 and 16, i.e., during the period of corpora lutea (CL) regression. In pregnant gilts, PGF in uterine flushings increased markedly between Days 10 and 18. Total recoverable PGF on Day 18 of the estrous cycle was only 464.5 ± 37.6 ng as compared to 22,688.1 ± 1772.4 ng on Day 18 of pregnancy. Total recoverable protein was also higher (P<.01) in pregnant gilts. These data indicate that PGF synthesis and secretion by the uterine endometrium and/or conceptuses is not inhibited during pregnancy and suggest that PGF is sequestered within the uterine lumen of pregnant gilts, as is the total protein component of endometrial secretions referred to as histotroph.     

Interaction of 4-hydroxylated estradiol and potential-sensitive Ca2+ channels in altering uterine blood flow during the estrous cycle and early pregnancy in gilts

This study was conducted to define further the role of catechol estrogens (CE) as intermediates in estrogen-stimulated uterine hyperemia. Previous studies from our laboratory strongly suggest that changes in uterine blood flow (UBF) result from alterations in uterine arterial tone (distensibility) and/or contractility (reactivity to alpha 1-adrenergic agonists). Tone changes appear to set the baseline rate of flow, whereas contractility changes result in short-term reductions in luminal diameter. Changes in uterine arterial tone and contractility result from alterations in Ca2+ uptake through potential-sensitive channels (PSCs) and receptor-operated channels (ROCs), respectively. Uterine and mesenteric arteries were removed from 6 gilts at estrus (Day 0), 9 gilts on Day 13 of gestation (high estrogen, high UBF), and 8 gilts on Day 13 of the estrous cycle (low estrogen, low UBF). Arterial measurements included initial tone (baseline perfusion pressure [BPP] to a constant intraluminal flow) and increased tone after exposure to KCl, the contractility in response to the alpha 1-agonist phenylephrine, and specific uptake of 45Ca before and after exposure to the CE 4-hydroxylated estradiol (4OH-E2). Contractility of uterine arteries from Day 13 nonpregnant (NP) and Day 13 pregnant (P) gilts to phenylephrine were similar and significantly greater (p less than 0.01) than contractility of vessels from estrous gilts. The BPP and responses of uterine arteries from Day 13 NP gilts to KCl were greater (p less than 0.05) than the BPP and responses of arteries from Day 13 P and estrous gilts, which were similar to each other.(ABSTRACT TRUNCATED AT 250 WORDS)     

Concentrations of 13, 14-dihydro-15-keto-prostaglandin F(2)alpha, estradiol-17beta and progesterone during the peripubertal period in heifers

Twenty prepubertal Holstein heifers were utilized to assess plasma 13, 14-dihydro-15-keto-prostaglandin F(2)alpha (PGFM), serum progesterone (P(4)) and estradiol-17beta (E(2)) concentrations as well as the E(2):P(4) ratio during the onset of puberty in cattle. All animals were maintained as a group along with a sterile marker bull to assist in the detection of estrus. Upon detection of the first estrus (Day=O), daily blood samples were collected from a jugular vein until the heifers had completed 3 estrous cycles. The average body weight and age at first estrus were 247.6+/-4.8 kg and 304.0+/-7.5 days, respectively. Frequency of abnormal length estrous cycles was greater (P<0.02) during the first (40%) and second (35%) cycles than during the third estrous cycle (0%). All heifers had normal cycle lengths (18 to 24 days) by the third estrous cycle. Serum P(4) was greater during the third cycle (P<0.05) from Day 10 to Day 4 before the next estrus compared with the same period of the first estrous cycle. Serum E(2) did not peak until the day of estrus in the first cycle, whereas E(2) reached a maximal level 2 days before estrus in the third estrous cycle. Serum E(2) was higher (P<0.0001) 2 days before estrus in the third cycle than in the first estrous cycle. Plasma PGFM reached maximum concentrations 3 days before estrus in the third cycle compared with 1 day before estrus at the end of first estrous cycle. As estrus approached during the third cycle, PGFM rose 1 day before E(2) rose and P(4) declined, while the rise in PGFM and E(2) occurred simultaneously, with P(4) declining at the end of the first estrous cycle. During diestrus, the E(2):P(4) ratio was lower (P<0.07) in the third cycle than in the first, but it was higher (P<0.04) at estrus and 1 day before in the third estrous cycle. These data reveal a high incidence of abnormal length estrous cycles during the first two estrous cycles of the peripubertal period, and demonstrate anomalies in uterine and ovarian endocrine activity during the peripubertal period in cattle.     

Effects of prolactin on conceptus survival and uterine secretory activity in pigs

Hypoprolactinaemia was induced by bromocriptine (CB154; 100 mg/day) which decreased circulating prolactin by 40% (P less than 0.06), but did not affect conceptus survival at Day 25 when administered on Days 10-16 when compared to saline:ethanol-treated control gilts. Bromocriptine or vehicle was administered to cyclic gilts on Days 10-11, oestradiol valerate was injected on Day 11 and uterine flushings were collected on Day 12. Total recoverable protein and uteroferrin in uterine flushings were not affected by treatment. However, leucine aminopeptidase activity (P less than 0.02) and total recoverable Ca2+, Na+, K+ and Cl- (P less than 0.05) were decreased in uterine flushings of gilts that received bromocriptine, suggesting that hypoprolactinaemia decreased general secretory activity of the endometrial epithelium and modulated ionic changes, respectively, in the uterine environment of pigs. Subcutaneous administration of pig prolactin (1 mg/12 h) increased (P less than 0.001) serum prolactin 4.5-fold. The interaction between hyperprolactinaemia and progesterone, without oestrogen, on components of uterine flushings were determined using gilts that received progesterone (200 mg/day) and prolactin or saline on Days 4-14 after ovariectomy on Day 4. On Day 15, there were no differences (P greater than 0.05) in any of the uterine secretory components measured. Hyperprolactinaemia (1 mg pig prolactin on Days 6-11) enhanced overall uterine secretory response on Day 12 to oestradiol (5 mg) administered on Day 11 compared to gilts that received 1 ml saline on Days 6-11 of the oestrous cycle. Total recoverable protein and leucine aminopeptidase activity were greater (P less than 0.05) for oestradiol-treated gilts, but effects of prolactin were not significant. Total recoverable glucose (P less than 0.01), PGF-2 alpha (P less than 0.02), uteroferrin (P less than 0.01) and specific activity of uteroferrin (P less than 0.001) were increased by prolactin and oestradiol, but not oestradiol alone. Calcium (P less than 0.05), chloride (P less than 0.05) and potassium (P less than 0.01) were increased in response to oestradiol. These results indicate an interaction between oestradiol and prolactin, but not progesterone and prolactin, which enhances secretion of some products of the pig uterine endometrium.     

Effect of estradiol-17beta on PGF and total protein content in bovine uterine flushings and peripheral plasma concentration of 13, 14-dihydro-15-keto-PGF(2alpha)

Two experiments were conducted to examine the effect of estradiol-17beta (E(2)-17beta) on content of immunoreactive prostagladin F(2)alpha (PGF, ng) and total protein (TUP, mg) in uterine flushings, as well as concentrations of 13, 14-dihydro-15-keto-PGF(2)alpha (PGFM) in plasma (Pg/ml). In experiment 1, Holstein heifers were utilized in a single reversal trial in which either E(2)-17beta (3 mg in 2 ml saline/ethanol 50:50; n=5) or vehicle alone (n=6) were given intravenously on day 14 or 15 of the estrous cycle (Period 1) following an induced estrus (day of estrus = day 0). Treatment (Trt) groups were reversed in Period 2 (Day 14 or 15 of the second estrous cycle). Jugular venous plasma was obtained before treatment (Oh), and at 5, 6, and 9h posttreatment (PT). Uterine flushings were collected nonsurgically in vivo , per cervix, via Foley catheter at 6h PT (20 ml of .9% saline per uterine horn). E(2)-17beta did not significantly alter (E(2)-17beta vs vehicle; x(-) +/- S.E.M.) PGF (1674 +/- .11 +/- 338.39 vs 1889.91 +/- 400.24 ng; P> .10) or TUP (33.25 +/- 2.57 vs 39.16 +/- 3.04 mg; P > .10). However, E(2)-17beta increased (P < .05) plasma PGFM (E(2)-17beta vs vehicle) after treatment (0h, 113.2 vs 163.8; 5h, 312.5 vs 203.9; 6h, 324.5 vs 198.0; 9h, 323.2 vs 246.8, pg/ml). In experiment 2, crossbred beef cattle received comparable treatments of either E(2)-17beta (n=5) or vehicle (n=5) on day 14 or 15 postestrus. Jugular venous plasma was obtained at 0h PT, and at 6h PT. Uterine flushings (1.9% saline, 20 ml per uterine horn) and peripheral plasma were collected at slaughter. Estradiol-17beta increased PGF (30.07 +/- 5.94 vs 8.46 +/- 2.01 ng; P> <.05) in uterine flushings as well as PGFM in plasma (E(2)-17beta : 55.82 +/- 19.13 pg/ml, at 0h and 89.31 +/- 14.02 pg/ml, at 6h, vs saline: 103.46 +/- 50.73 pg/ml, at 0h and 17.78 +/- 14.22, at 6h). Estradiol-17beta stimulated uterine production and release of PGF and protein as measured in flushings (experiment 2) as well as plasma PGFM responses (experiments 1 and 2). Uterine and/or cervical stimulation of experiment 1 may have masked uterine response to E(2)-17beta.     

Reproductive function of mares given daily injections of prostaglandin F2alpha beginning at day 42 of pregnancy

Mares at Day 42 of pregnancy received daily intramuscular (i.m.) injection of 5 mg of prostaglandin F2alpha (PGF(2alpha)) until the beginning of the first (Group I, n = 3) or second estrous cycle (Group II, n = 2). All mares aborted 3 to 4 d after the first injection; they displayed estrus 2 to 6 d after this injection. As determined by palpation per rectum and serum progesterone levels, each estrus was accompanied by an ovulation. Endometrial cups did not regress after PGF(2alpha) treatment since serum samples from the mares contained pregnant mare serum gonadotropin (PMSG) for at least 30 d after first injection, as determined by mare immunopregnancy test. After the first estrus, two of three mares in Group I displayed a prolonged diestrus (> 25 d). In contrast, the first estrous cycle was short (8 to 12 d) for mares in Group II. Serum progesterone levels in the first 6 d postovulation were lower (P < 0.05) for Group II than for Group I, indicating that formation of the corpus luteum was impaired by daily injections of PGF(2). Results indicate that 1) daily injections of PGF(2alpha) can induce abortion in mares at Day 42 of pregnancy, 2) abortion is followed by estrus and ovulation, 3) the endometrial cups do not regress as a result of this treatment, and 4) daily injections of PGF(2) can impair early corpus luteum development.     

Role of prostaglandins in development of porcine blastocysts

Rapid elongation of porcine blastocysts between Days 11 to 12 of pregnancy coincides with an increase in uterine luminal content of prostaglandins. The present study evaluated the effect of two prostaglandin synthesis inhibitors (indomethacin and flunixin meglumine) on elongation of porcine blastocysts from spherical to filamentous forms between Day 11 to 12 of pregnancy. Gilts were hemi-hysterectomized on Day 11 of pregnancy. The excised uterine horn was flushed with 0.9% saline and diameter of blastocysts recovered were measured. Immediately following surgery, pregnant gilts were assigned to receive either: 1) vehicle every 4 h, 2) flunixin meglumine (banamine) every 4 h, or 3) indomethacin every 12 h. The remaining uterine horn was removed and flushed after the time of blastocyst elongation estimated for each gilt on basis of blastocyst development in the first horn. Uterine flushings were analyzed for total calcium, protein, acid phosphatase activity, estrone, estradiol-17 beta and prostaglandin F. Pretreatment blastocyst diameter was similar for all groups and ranged from 1 mm to 20 mm. Treatment of gilts with either banamine or indomethacin effectively inhibited (P less than 0.001) the increase in uterine luminal content of PGF. Total calcium, estrone and estradiol-17 beta were not influenced by treatment. Total uterine luminal protein and acid phosphatase activity were reduced (P less than 0.05) in banamine treated gilts compared to those receiving vehicle or indomethacin treatments. Although total PGF recovered in uterine flushings was reduced during the period of blastocyst elongation, treatment with PGF synthetase inhibitors failed to block rapid elongation of blastocysts from the spherical to filamentous forms.     

Effect of pregnancy and exogenous ovarian steroids on endometrial prolactin receptor ontogeny and uterine secretory response in pigs

During gestation, pigs have constant circulating levels of prolactin (PRL), and lack decidual PRL and placental lactogens. Effects of PRL on uterine physiology in pigs may be due to changes in endometrial PRL receptors. In this study, effects of the conceptus and cyclic hormonal environment on endometrial PRL receptors were investigated. Endometrial PRL receptor numbers were similar between Days 8 and 15 for cyclic gilts. In contrast, endometrial PRL receptor numbers for pregnant gilts were similar between Days 8 and 11, then increased (p less than 0.05) on Day 12 and remained elevated between Days 14 and 30. This day-by-status interaction approached significance (p less than 0.06) and overall receptor numbers were higher (p less than 0.01) for pregnant than for cyclic gilts. Pig conceptuses secrete estrogen between Days 11 and 12; therefore, regulation of endometrial PRL receptors by acute administration of estradiol was investigated. Uterine flushings and endometrium were collected from one uterine horn of cyclic gilts on Day 11; then, at 1, 6, 12, and 24 h following a single injection of estradiol valerate (EV; 5 mg, into adipose tissue), uterine flushings and endometrium were collected from the second uterine horn. Endometrial PRL receptor numbers were higher (p less than 0.05) at both 1 h and 6 h after treatment with EV and then decreased (p less than 0.02) by 12 h to below pretreatment values. In uterine flushings, total recoverable protein (p less than 0.05), uteroferrin (p less than 0.01), leucine aminopeptidase (p less than 0.05), calcium (p less than 0.03), sodium (p less than 0.01), and potassium (p less than 0.05) increased between 12 and 24 h following EV treatment.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of recombinant alpha interferons on fertility and interestrous interval in sheep

In Experiment 1, 12 unmated cyclic ewes received twice-daily intrauterine injections on Days 12 to 14 of one of the following treatments: 1) ovine conceptus secretory proteins (oCSP) containing 25 mug of ovine trophoblast protein-1 (oTP-1) as determined by RIA; 2) 25 or 50 mug recombinant human interferon alpha1 (rhlFN); or 3) 1500 ug of serum proteins (oSP) from a Day-16 pregnant ewe (estrus = Day 0) per uterine horn. Ewes receiving oCSP had longer interestrous intervals (27 +/- 2 days; P<0.05) than ewes receiving oSP (17 +/- 2 days). Ewes receiving either dose of rhlFN had an interestrous interval of 16 +/- 2 days which did not differ (P>0.10) from that of oSP-treated ewes. In Experiment 2, 59 normally cycling ewes, mated on Day 0, received twice-daily intramuscular injections of either 2 mg recombinant bovine interferon alpha1 (rblFN) or placebo on Days 12 to 15 post estrus. On Day 16, pregnancy was confirmed by flushing a morphologically normal conceptus from the uterus. Pregnancy rates for rblFN-treated (80%) and placebo-treated (62%) ewes were not different (P>0.10). Uterine flushings and conceptus-conditioned medium were assayed for oTP-1. Total oTP-1 in conceptus-conditioned culture medium was higher (P<0.02) when conceptuses were from placebo-treated (104 +/- 14 mug/conceptus) than from rblFN-treated (56 +/- 12 mug/conceptus) ewes; while total oTP-1 in uterine flushings was similar (P>0.10) for placebo-treated (132 +/- 15 mug/conceptus) and rblFN-treated (147 +/- 17 mug/conceptus) ewes. The interval from mating to subsequent estrus following conceptus removal was 31 +/- 1 and 28 +/- 1 days for pregnant ewes treated with rblFN and placebo, respectively. Interestrous intervals for nonpregnant ewes were longer (P<0.02) for rblFN-treated (27 +/- 3 days) than for placebo-treated (18 +/- 2 days) ewes.     

Relationship between variation in conceptus development and differences in estrous cycle duration in ewes

The objective of this study was to examine conceptus development on Day 13 in ewes with estrous cycles of different durations. Ewes (n = 80) were screened according to the length of their estrous cycles. Subsequently, ewes that had either SHORT or LONG cycles were utilized (15.9 +/- 0.1 or 18.6 +/- 0.4 days; mean +/- SEM, p less than 0.01; 10 ewes per group). Jugular blood samples were collected twice daily from Days 0-6 after mating and then once a day until slaughter on Day 13. Concentrations of progesterone in plasma and amounts of ovine trophoblast protein-1 (oTP-1), protein, and prostaglandins (PG) E2 and F2 alpha (PGF2 alpha) in uterine flushings were determined. Concentrations of progesterone were greater (Day by treatment interaction, p less than 0.01) on Days 2-4 for ewes in the SHORT group. On Day 5 and thereafter, progesterone concentrations were not different between groups. More (p less than 0.05) oTP-1 and protein (8.1 +/- 1.3 micrograms and 1.8 +/- 0.3 micrograms versus 2.4 +/- 1.3 micrograms and 0.8 +/- 0.3 mg) were recovered from uterine flushings from ewes in the SHORT versus LONG groups, respectively. The ratio of PGE2:PGF2 alpha was higher (p less than 0.06) in flushings from ewes in the SHORT versus LONG group (1.4 +/- 0.2 versus 0.9 +/- 0.2, respectively). Conceptuses were classified by stage of morphological development. Conceptus development was accelerated (p less than 0.01) in ewes of the SHORT group, as shown by filamentous conceptuses recovered from 78% versus 0% of SHORT versus LONG ewes, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Uterine-specific proteins in luminal secretions of swine leukocyte antigen-inbred miniature swine with cystic endometrial hyperplasia

Uterine-specific proteins were evaluated in luminal secretions of Swine Leukocyte Antigen (SLA)-inbred miniature swine with cystic endometrial hyperplasia (CEH) by polyacrylamide gel electrophoresis (PAGE) and Sephacryl S-200 chromatography. CEH and non-CEH (NCEH) pigs (n = 23) were killed on Days 4, 9, and 15 of the estrous cycle (estrus = Day 0) and reproductive tracts were excised for collection of serum and uterine luminal protein. Uterine luminal protein was greater (p less than 0.05) on Day 9 than on Days 4 and 15 (42.9 vs. 6.1 and 29.4 mg, respectively) for CEH pigs and Days 4, 9, and 15 (8.5, 10.1, and 25.6 mg, respectively) for NCEH pigs. The presence of the uterine-specific acidic and basic proteins, as revealed by PAGE, was affected (p less than 0.025) by day of the cycle and CEH condition. All Day 15 NCEH pigs (4 of 4) produced the complete profile of these proteins, whereas none of the uterine protein samples representing other treatment groups contained them. Some minor acidic protein components were present in cystic fluids from CEH pigs, but these fluids lacked the typical uterine-specific proteins. PAGE analysis of Sephacryl S-200 fractions from uterine fluids of Day 15 NCEH pigs revealed the uterine-specific proteins in fractions IV (Mr 40,000) and V (Mr 15,000). The results of the investigation demonstrate an impairment in the secretion of uterine-specific proteins in cyclic SLA miniature swine with cystic endometrial hyperplasia.     

Plasma and uterine cortisol, progesterone and protein changes in pseudopregnant gilts treated with hydrocortisone acetate

To determine the effects of cortisol concentrations during pregnancy, gilts, made pseudopregnant through twice daily administration of 5 mg estradiol benzoate on Days 11 to 15 (Day 0 = first day of estrus), received either 5 mg/kg body weight of hydrocortisone acetate (HA) in sesame oil (n=5) or sesame oil alone (n=6) twice daily on Days 21 to 30. Blood samples (20 ml) were collected on Days 11, 21 and 31. Uterine flushings were obtained surgically on Day 31. The HA-treated gilts had higher (P<0.01) plasma cortisol (295.7 vs 35.6 ng/ml) and lower (P<0.01) plasma progesterone (8.9 vs 17.8 ng/ml) concentrations than did controls. Uterine flushings recovered from HA-treated gilts had significantly (P<0.01) higher cortisol (9.9 vs 5.6 ng/ml), lower progesterone (2.1 vs 6.8 ng/ml) and lower total protein (8.3 vs 21.4 mg/ml) levels than the control animals. Cortisol measured in the uterine flushings of the gilts was more than 85% unbound. Plasma corticosteroid binding globulin binding capacity was lower (P<0.05) in HA-treated gilts (7.4 nmol/l) than in the control (38.7 nmol/l) animals on Day 31. Corpora lutea (CL) number and weight were lower (P<0.05) in HA-treated than control gilts. However, progesterone concentration per CL did not differ between the 2 groups. These results indicate that elevated cortisol levels can alter endocrine and uterine functions related to pregnancy using the pseudopregnant gilt as a model.     

Uterine specific antigens in the ewe

Uterine flushings from ewes on days 0, 3, 6, 9, 12 and 15 of the estrous cycle were analyzed for total protein content. Flushings from days 9, 12 and 15 had greater (P<.01) amounts of protein than those from 0, 3 and 6. Antisera to uterine fluids from ewes at day 10 to 12 or day 14 to 15 of pregnancy detected two uterine-specific antigens in uterine flushings at day 7, 11 and 15 but not at days 0 and 3 of the cycle. A third uterine antigen was also detected in kidney tissue extracts. All three antigens were present in endometrial extracts at each stage examined. Progesterone, or estrogen plus progesterone, administration to ovariectomized ewes induced the appearance of the two uterine-specific antigens. The third antigen was detectable even in ovariectomized ewes. No pregnancy-specific antigens were detected in flushings from days 7, 11 or 15 of gestation. The effect of pregnancy on endometrial protein synthesis was examined in vitro . No differences were seen in the incorporation of (3)H-leucine in day 11 pregnant or nonpregnant or in day 14 pregnant or nonpregnant endometrium. No differences in total uterine lumenal protein were observed. Endometrial secretions, obtained by conditioning media with endometrial explant cultures, were evaluated to assess their effect on protein synthesis in day 11 embryos cultured in vitro . No significant effects of endometrial secretions or serum were observed.