奶牛输卵管平滑肌前列腺素类受体的分析研究

本研究选用了前列腺素类化合物(Prostaglandin E2（PGE2）、Prostaglandin F2α（PGF2α）、Prostaglandin D2（PGD2)）和受体选择性激动剂（Butaprost、U-46619）,用多道生理信号采集系统测定其对体外分离的奶牛输卵管峡部及壶腹部平滑肌收缩的影响,以此初步揭示受体的种类。结果发现,PGE2和Butaprost均抑制了奶牛输卵管峡部、壶腹部的自发性收缩运动,呈现明显的浓度依存性舒张反应;PGF2α在高浓度(1～10 μmol/L)下,使峡部和壶腹部的自发性收缩运动有了显著增强;PGD2在低浓度时轻微抑制了壶腹部平滑肌的收缩,但在高浓度(1～10 μmol/L)时加强了峡部和壶腹部平滑肌的收缩;U-46619从低浓度便引起了输卵管峡部和壶腹部平滑肌的强烈收缩。结果表明,EP4、EP2、FP、DP和TP受体同时存在于奶牛输卵管平滑肌上,能与内源性前列腺素类结合并参与调节输卵管平滑肌的自发性收缩。     

Determination of the estrogenic activity of wild phytoestrogen-rich Pueraria mirifica by MCF-7 proliferation assay

The aim of this study was to evaluate the estrogenic activity of tuberous samples of wild, phytoestrogen-rich Pueraria mirifica collected from 28 out of 76 provinces of Thailand by MCF-7 proliferation assay. The plant extracts were administered to MCF-7, ER alpha positive human mammary adenocarcinoma cell cultures, for 3 days at dosages of 0.1, 1, 10, 100 and 1,000 microg/ml and were compared with 17 beta-estradiol at concentrations of 10(-12)-10(-6) M. The mean P. mirifica population at 1 mug/ml exhibited significant proliferation. Two plant samples exhibited levels of proliferation in MCF-7 that were similar to 17beta-estradiol. The mean P. mirifica populations at 100 and 1,000 microg/ml exhibited significant cytotoxicity in MCF-7. Analysis of the estrogenic activity of puerarin, representative of major isoflavonoids in P. mirifica tubers, revealed proliferation in MCF-7 only at the highest dose (10(-6) M) that was 10(2)-10(5) times less active than 17 beta-estradiol. Puerarin and 17 beta-estradiol at concentration of 10(-12)-10(-6) M exhibited no cytotoxicity in MCF-7.     

Spontaneous contractions of intestinal smooth muscle re-aggregates from the new-born rat triggered by thromboxane A2

Isolated smooth muscle cells from the small intestine of new-born rats were prepared by enzymatic digestion. These cells re-aggregate after 1 day in culture to clusters. The re-aggregates show spontaneous rhythmical contractions at 37 degrees C with a frequency (13.1 +/- 0.8 min-1, n = 49), which is similar to that of the intact smooth muscle layer. The cholinergic agonist carbachol (5 x 10(-5) mol l-1) caused an increase in the frequency of the spontaneous contractions often ending in a permanent contraction. A similar effect was achieved with the thromboxane A2 (TXA2) agonist, U-46619 (10(-5) mol l-1). In contrast, both the TXA2 receptor blocker, Bay u3405 (5 x 10(-4) mol l-1), as well as the Ca2+ channel blocker, verapamil (5 x 10(-5) mol l-1), suppressed the spontaneous contractions. The observed contractility was insensitive against the neuronal blocker tetrodotoxin (10(-6) mol l-1). These analyses of video images were supported by the measurement of relative changes in the intracellular Ca2+ concentration with the Ca(2+)-sensitive dye, fura-2. Spontaneous contractions were paralleled by spikes in the intracellular Ca2+ concentration, which were abolished by Bay u3405, but stimulated by U-46619 or carbachol. In summary, these results obtained at re-aggregates of intestinal smooth muscle cells support the hypothesis of a role of TXA2 in the generation of spontaneous intestinal smooth muscle contractions in vitro.     

Evaluation of use of progesterone to counteract zearalenone toxicosis during early pregnancy in gilts.

It has been shown that zearalenone disrupts early pregnancy in swine without altering intrauterine content of estradiol 17 beta or progesterone, embryo migration, or estradiol-17 beta synthesis by blastocysts. However, serum concentrations of progesterone were reduced 2 to 3 weeks after mating in gilts that ingested zearalenone. Therefore, progesterone was administered to gilts during early pregnancy to determine whether it could counteract the detrimental actions of zearalenone on embryonic development. Thirty-two crossbred gilts (Hampshire x Chester White x Yorkshire x Duroc) were assigned randomly to a 2 x 2 factorial arrangement of treatments: zearalenone (Z); zearalenone plus progesterone (ZP); progesterone (P); or control (C). From postmating days 4 to 15, Z- and ZP-treated gilts were fed 1 mg of Z/kg of body weight, and P-treated and C gilts were fed ethanol as vehicle in a corn-soybean diet. On postmating days 3 to 15, P- and ZP-treated gilts were injected IM with 100 mg of progesterone, and C and Z-treated gilts were injected with progesterone carrier (15% ethanol, 15% benzyl alcohol, 70% propylene glycol). Blood was collected from gilts by puncture of the jugular vein daily from days 3 to 15, on alternate days from days 17 to 31, and then twice weekly until the end of the experiment. Fetal development was assessed in Z- and ZP-treated gilts on postmating day 47.6 +/- 2.9 by cesarean section and in P-treated and C gilts at slaughter on postmating days 51.2 +/- 3.2. Serum concentrations of progesterone in P-treated gilts were greater on days 7 to 8, 10 to 15, 17, and 19 than in C gilts. Serum concentrations of progesterone were greater on days 8, 10, and 12 in ZP-treated than in C gilts. However, serum concentrations of progesterone were lower in ZP-treated gilts than in C gilts on postmating days 19 to 31.(ABSTRACT TRUNCATED AT 250 WORDS)     

Validating a commercially available enzyme immunoassay for the determination of 17beta-estradiol and progestogens in the feces of cheetahs (Acinonyx jubatus): a case report.

Fecal 17beta-estradiol and progestogens excretion was monitored in adult, female cheetahs (Acinonyx jubatus; n = 2), ZGG-12301 (born 3 April 1993), gonadotrophin treated and ZGT-3301, (born 19 August 1993), nontreated, for 120 days using commercially available plate enzyme immunoassay kits prepared for human serum or plasma. There were significant differences (P < 0.001) between baseline and peak concentrations of both hormone measures. Female ZGG-12301, which conceived, but this pregnancy resulted in an unobserved spontaneous abortion, showed no significant difference (P > 0.05) between baseline and gestation 17beta-estradiol values; fecal 17beta-estradiol excretion during pregnancy was statistically different (P < 0.001) from excretion during the nonpregnancy period. Baseline progestogen concentrations were different from pregnancy (P < 0.001) and postovulatory (P < 0.01) concentrations, and progestogen concentrations during pregnancy period were different (P < 0.001) from postovulatory concentrations. In the nontreated cheetah (ZGT-3301), basal and increased progestogen concentrations were statistically different (P < 0.01). On the basis of 17beta-estradiol excretory patterns, duration of the estrous cycle (x +/- SEM) was 13.2 +/- 2.2 days. These results suggest that the enzyme-linked immunosorbent methods reported in this study were capable of quantifying reproductive hormones in fecal extracts of cheetahs and could be a practical alternative to other enzyme-linked immunosorbent assays which require more complex procedures.     

血根碱对大鼠离体子宫平滑肌收缩的影响及其机制研究

试验旨在研究血根碱对大鼠离体子宫平滑肌活动的影响。分离8周龄SD雌性未孕大鼠子宫平滑肌,通过BL-420F生物信号采集系统记录子宫平滑肌收缩频率和收缩幅度,计算子宫平滑肌活力。以硫酸阿托品、盐酸普萘洛尔、盐酸苯海拉明及盐酸雷尼替丁为阻断剂,观察血根碱对子宫平滑肌M、β、H₁、H₂受体的关系,探讨血根碱对子宫平滑肌的作用机制。结果显示,血根碱组和元胡止痛片组对缩宫素所致大鼠离体子宫平滑肌收缩频率、收缩幅度和活力均有显著的抑制作用（P<0.05）;应用H₁受体阻断剂苯海拉明和H₂受体阻断剂雷尼替丁后,血根碱对子宫平滑肌抑制作用基本被阻断,而应用M受体阻断剂阿托品,β受体阻断剂普萘洛尔后,血根碱对子宫平滑肌收缩仍具有显著的抑制作用（P<0.05）。综上所述,血根碱对大鼠子宫平滑肌活力具有显著的抑制作用,可能是通过抑制H₁、H₂受体实现,与M、β受体无关。     

Effect of Sanguinarine on Active Capacity of Isolated Rat Uterine Smooth Muscle in vitro and Its Mechanism

The study was aimed to explore the effects of the sanguinarine on activity of isolated rat uterine smooth muscle in vitro. The effect of the sanguinarine on activity of the isolated myometrium of non-pregnant Sprague-Dawley rats eight weeks old was recorded by BL-420F four channels physiological recorder. Four antagonists, atropine sulfate, ranitidine hydrochloride, propranolol hydrochloride and diphenhydramine hydrochloride were used to study their mechanism, respectively. The results showed that sanguinarine and Yuan hu painkillers markedly inhibited the frequency, amplitude and activity of uterine contractions induced by oxytocin injection (P<0.05). The inhibitory effect of sanguinarine on uterine muscle contractions was blocked after using diphenhydramine hydrochloride (H₁-receptor antagonist) and ranitidine hydrochloride (H₂-receptor antagonist). However, after using atropine sulfate (M-receptor antagonist) and propranolol hydrochloride (β-receptor antagonist), sanguinarine also significantly inhibited the contractions of rat uterine smooth muscle (P<0.05). It was concluded that the effect of sanguinarine on activity of uterine smooth muscle in rats was mainly associated with H₁ receptor or H₂ receptor but not M receptor or β receptor.     

Characterization of the in vitro responses of equine cecal longitudinal smooth muscle to endothelin-1

OBJECTIVE: To characterize the in vitro response of equine cecal longitudinal smooth muscle (CLSM) to endothelin (ET)-1 and assess the role of ETA and ETB receptors in those ET-1-induced responses. ANIMALS: 36 horses without gastrointestinal tract disease. PROCEDURE: To determine cumulative concentration-response relationships, CLSM strips were suspended in tissue baths containing graded concentrations of ET-1 (10(-9) to 10(-6)M) with or without BQ-123 (ETA receptor antagonist); with or without IRL-1038 (ETB receptor antagonist); or with both antagonists at concentrations of 10(-9), 10(-7), and 10(-5)M. To determine the percentage change in baseline tension of CLSM, the areas under the curve during the 3-minute periods before and after addition of each dose were compared. Also, the effects of ET-1 and a combination of selective ETA and ETB receptor antagonists on electrically evoked contractions were studied. RESULTS: ET-1 caused sustained increases in CLSM tension in a concentration-dependent manner. Contractile responses to ET-1 were not significantly inhibited by either BQ-123 or IRL-1038 alone at any concentration; however, responses were significantly inhibited by exposure to the antagonists together at a concentration of 10(-5)M. Electrical field stimulation did not change the spontaneous contractile activity of CLSM and did not significantly alter the tissue response to ET-1, BQ-123, or IRL-1038. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that ET-1 has a contractile effect on equine CLSM that is mediated via ETA and ETB receptors. In vitro spontaneous contractions of equine CLSM apparently originate in the smooth muscle and not the enteric nervous system.     

Characterization of effects of zearalenone in swine during early pregnancy

Mature gilts (n = 16) were hand mated and randomly assigned to 1 of 4 groups of 4 gilts each. Treated gilts had 108 mg of purified zearalenone added to their diet on postmating days (PMD) 2 to 6, 7 to 10, or 11 to 15. Control gilts were given the same diet without added zearalenone. On PMD 6, 10, and 15, control gilts had venous cannulas placed in the jugular vein, and blood samples were taken at 20-minute intervals for 4 hours before feeding and 4 hours after feeding. Samples were collected from treated gilts on the last day that zearalenone was consumed. Samples were analyzed for follicle stimulating hormone, luteinizing hormone (LH), and prolactin. Single blood samples were taken by venipuncture on PMD 8, 12, 16, 20, 24, and 28 and at euthanasia and were analyzed for serum concentration of progesterone and estradiol-17 beta. All gilts were euthanatized 30 to 32 days after mating, and fetal development was assessed. Three gilts that were given zearalenone on PMD 7 to 10 were not pregnant and had regressing corpora lutea on the ovaries at euthanasia. All other treated and control gilts were pregnant. Serum samples from treated gilts on PMD 10 and 15 had lower mean prolactin concentrations than did those from controls. The number of LH spikes were fewer (P less than 0.05) in gilts that were given zearalenone on PMD 15 compared with those in controls on PMD 15. Serum progesterone concentrations indicated that corpora lutea regressed between PMD 20 and 28 in nonpregnant gilts.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of zearalenone on various components of rabbit uterine tubal fluid

A study was conducted to determine whether an orally administered mycotoxin, zearalenone (11.5 mg/kg of body weight/day), enters the uterine tubal fluid (UTF) of rabbits and to evaluate its influence on certain constituents of UTF. Using high-performance liquid chromatography, the concentration of zearalenone in UTF was maximal on day 1 of initial exposure to the compound, then decreased rapidly to half the peak concentration by day 5. The disappearance curve for zearalenone in UTF was linear throughout the treatment period (10 days) and was not detectable within 3 days after the last administration of zearalenone and the initiation of pregnancy (does were bred on day 10 of the zearalenone treatment). Zearalenone increased the volume of UTF (P less than 0.05) in estrous does, but decreased the pH (P less than 0.05) and the total free amino acid concentration (P less than 0.05) of UTF, compared with pretreatment values. The concentrations of several trace elements and amino acids known to be of critical importance in early embryonic development were altered by zearalenone treatment and/or pregnancy. Gross developmental anomalies were not evidenced when fetuses were examined on days 28 to 30 of gestation. It was concluded that zearalenone or associated metabolites affect factors that influence fertility during the early preimplantation period. Furthermore, the analysis of UTF appears to be an effective screening method for assessing certain potential reproductive toxicants.     

In vitro effects of erythromycin, lidocaine, and metoclopramide on smooth muscle from the pyloric antrum, proximal portion of the duodenum, and middle portion of the jejunum of horses

OBJECTIVE: To evaluate effects of erythromycin, lidocaine, and metoclopramide on smooth muscle of the pyloric antrum (PA), proximal portion of the duodenum (PD), and middle portion of the jejunum (MJ) of horses. Sample Population-Strips of smooth muscle from 7 horses. PROCEDURE: Isolated muscle strips were suspended in a bath and attached to isometric force transducers. Once stable spontaneous contractions were observed, agents were added. Isometric stress responses were compared with the amplitude of spontaneous contractions. RESULTS: A single dose of erythromycin to the PA increased contractile amplitude (CA) for the longitudinal smooth muscle (mean +/- SEM, 76+/-16 g/cm2) but decreased CA for circular smooth muscle (-79+/-23 g/cm2). The inhibitory effect was decreased by tetrodotoxin, N(G)-nitro-L-arginine methyl ester, and a vasoactive intestinal peptide antagonist. Erythromycin increased CA for the MJ, which was maximal at 10(-4)M (171+/-36 g/cm2). Lidocaine increased CA for the PD, which was maximal at 10(-4) M (60+/-5 g/cm2). Metoclopramide increased the CA, which was maximal at 10(-4) M for the PA (75+/-26 g/cm2), PD (279+/-33 g/cm2), and MJ (456+/-59 g/cm2). CONCLUSIONS: Regional differences in responses to erythromycin, lidocaine, and metoclopramide were evident in the gastrointestinal tract of horses. Metoclopramide increased CA in all tissues used, whereas erythromycin inhibited CA in circular smooth muscle but stimulated CA in longitudinal smooth muscle from the PA. Inhibition is caused by stimulation of inhibitory nerves and is mediated, in part, by nitric oxide and vasoactive intestinal peptide.     

The influence of nitric oxide on the contractile activity of the isolated porcine ovarian and uterine arteries

The aim of the present study was to investigate the influence of nitric oxide (NO) on the contractile activity of the isolated porcine ovarian and uterine arteries. Segments of the vessels, obtained from the pigs on days 1-5, 8-13 and 17-20 of the oestrous cycle, were mounted in the organ bath with Krebs-Ringer solution and contractile activity changes of the vessels were measured using isometric transducers. In Experiment I the arteries pretreated with norepinephrine (NE; 10(-7) M) were treated with sodium nitroprusside (SNP, 10(-8)-10(-4) M), a NO donor. In Experiment II administration of NE (10(-7) M) was preceded by treatment with Nomega-nitro-L-arginine methyl ester (L-NAME, 10(-8)-10(-6) M), an inhibitor of NO synthase. Donor of NO at doses of 10(-8)-10(-7) M did not affect (P>0.05) the contractility, while at doses of 10(-5)-10(-4) M caused a dose-dependent relaxation (P<0.05) of both ovarian and uterine arteries in all periods examined. Moreover, SNP at doses of 10(-6)-10(-4) M it caused significantly higher (P<0.05) relaxation of the ovarian arteries collected on days 8-13 as compared to the vessels from days 1-5 of the cycle. Pretreatment of the vessels with L-NAME caused a dose-dependent, significant (P<0.05) increase in the vasocontractile action of NE in both the ovarian and uterine arteries as compared to contractile activity of NE administered alone. Moreover, L-NAME pretreatment at a dose of 10(-6) M caused significantly higher (P<0.05) intensification of NE action in ovarian and uterine arteries collected on days 8-13 as compared to the vessels from days 1-5 (P<0.05) and 17-20 (P<0.05) of the oestrous cycle. Obtained results indicate that NO plays an important role in the regulation of the contractile activity of the isolated porcine ovarian and uterine arteries. Our data suggest that this action may be, at least in a part, dependent on the hormonal status of the organism.     

中药产复康对大鼠离体子宫平滑肌收缩功能的影响

为了观察中药制剂产复康对离体子宫平滑肌的收缩功能,测定了产复康对大鼠离体子宫平滑肌收缩功能和催产素引起的大鼠离体子宫平滑肌收缩功能的影响。结果发现低剂量产复康可以促进大鼠离体子宫平滑肌的收缩功能,提高子宫的活动性,高剂量则对子宫呈抑制作用;产复康对催产素引起的大鼠离体子宫平滑肌收缩功能具有抑制作用,且呈剂量-效应关系。产复康对大鼠离体子宫具有双向调节作用。     

Assessing estrogenic activity of pyrethroid insecticides using in vitro combination assays

Pyrethroid insecticides are among the most commonly used classes of insecticides worldwide, but their endocrine disrupting activities remain unclear. Therefore, in the present study, we examined the estrogenic activities of pyrethroid insecticides in E-screen and competition binding assays. In addition, we measured estrogen receptor (ER) protein and pS2 mRNA levels in human breast cancer cells (MCF-7 BUS) to clarify the mechanism of their estrogenicity. Seven pyrethroid insecticides (bioallethrine, cypermethrin, deltamethrin, fenvalerate, permethrin, sumithrin, and tetramethrin) were tested because of their worldwide usage. In addition, 17beta-estradiol was tested as a positive control. As expected, 17beta-estradiol significantly increased MCF-7 BUS cell proliferation at concentrations of 10(-11) M and above. Of the pyrethroid insecticides tested, only sumithrin increased MCF-7 BUS cell proliferation in a dose-dependent manner; the maximum induction of cell proliferation was observed at a dose of 10(-5) M. In the anti-estrogenic activity test, bioallethrin, fenvalerate, and permethrin significantly inhibited 17beta-estradiol-induced MCF-7 BUS cell proliferation at 10(-6) M, a concentration comparable to the effective dose (10(-9) M) of ICI 182,780, a pure ER antagonist. However, none of the pyrethroid insecticides competitively inhibited the binding of [(3)H]estradiol to rat uterus ERs in competition binding assays. Both 17beta-estradiol (10(-10) M) and sumithrin (10(-5) M) decreased the levels of cytosolic ERalpha and ERbeta protein expression significantly as compared with the vehicle control. In addition, 17beta-estradiol (10(-10) M) increased pS2 mRNA expression markedly, and sumithrin significantly increased pS2 mRNA levels in a dose-dependent manner. The other six compounds tested in the present study did not affect ER protein levels or pS2 mRNA levels. These results suggest that certain pyrethroid insecticides may be considered to be estrogen-like chemicals that act through pathways other than direct ER binding, and may function as endocrine modulators in both wildlife and humans.     

Estradiol, progesterone and cyclic nucleotides in the fluid of persistent follicles and luteal phase follicles in the estrus cycle in cows]

The objective of the present study was to compare the concentrations of 17 beta-estradiol, progesterone, cyclic adenosine monophosphate and cyclic quinosine monophosphate in the largest follicles of cows that persist for seven days after insemination following the preceding synchronization of oestrus and superovulation and in follicles of the luteal phase of cycle (5th-10th days). Animals included in the experiment were selected on the basis of rectal examination. Synchronization of oestrus was achieved in 24 crossbreds of Slovak Pied x Lowland Black Pied breeds (SS x Nc) using two doses of cloprostenol of Czechoslovak provenience Oestrophan Spofa, 500 micrograms in each, within 11 days. Serum gonadotrophin at the amount of 2500 I. U. was administered forty-eight hours before administration of the second dose PGF2 alpha. Experimental animals were inseminated after 72 hours. On the 7th day after mating the cows were killed at a slaughterhouse. Evaluated were only the ovaries of the 14 cows in which the persistent large follicles occurred. Ovaries of the 13 control cows in the luteal phase between the 5th-10th days were obtained at the slaughterhouse by the method after Ireland et al. (1980). Correct determination of the phase of sexual cycle was substantiated by determination of progesterone concentrations in blood serum. Follicular fluid was obtained from the largest follicles by aspiration and centrifuged in a cooled centrifuge at 3000 G. The concentrations of 17 beta-estradiol and progesterone in follicular fluid were determined using kits from URVJT at Kosice, designated RIA-test-ESTRA (SI-125-9) or RIA-test-Prog (SI-125-6).2+ persistent follicles (9.15 +/- 5.47 nmol.l-1).(ABSTRACT TRUNCATED AT 250 WORDS)     

Fate and residues of [4-14C]estradiol-17 beta after intramuscular injection into Holstein steer calves

Radiocarbon-labeled estra-1,3,5(10)-triene-3,17 beta-diol [4-14C-estradiol-17 beta; beta-estradiol] was suspended in commercial peanut oil and administered to each of three Holstein steer calves (142 to 170 kg body weight) by deep injection into neck muscle via 2.0 ml peanut oil carrier. The dosages were equivalent to .27 to .29 mg beta-estradiol/kg body weight. After dosing, radiocarbon was rapidly and almost totally eliminated in urine and feces. Most of the administered radiocarbon had been eliminated after 2 d, and by 11 d after treatment no radiocarbon was detectable in urine or feces of any calf. Of the total dose, 42.1 +/- 3.8% was excreted in urine and 57.7 +/- 5.2% was eliminated in feces. Analysis of noninjection site tissue samples (blood, brain, fat, kidney, liver and muscle) collected at sacrifice 14 d after treatment showed that none contained detectable radiocarbon residues, with the sensitivity limit for most tissues being 6 ppb beta-estradiol equivalent. Certain sections of muscle taken from the injection site area did contain detectable radiocarbon residues (as much as 69 ppb beta-estradiol equivalent), but total injection site area residues in each calf comprised less than .07% of the total administered dose. Radiocarbon in urine consisted primarily of alpha-estradiol, with much lesser amounts of estrone. Both compounds occurred as nonconjugates and as glucuronides. beta-Estradiol was not detected in urine. Radiocarbon in feces included primarily alpha-estradiol but also beta-estradiol and estrone, each in non-conjugated form. The fact that most of the intramuscular-administered beta-estradiol was eliminated in the feces strongly suggests a major role for biliary excretion in the disposition of this steroid by steer calves.     

Endocrine pathogenesis of postweaning anestrus in swine: response of the persistently anestrous sow to hormonal stimuli

The endocrine function of the individual components of the hypothalamo-hypophyseal-ovarian axis of the postweaning anestrous sow was evaluated by monitoring the sow's response to exogenous estradiol, gonadotropin releasing hormone (GnRH), and gonadotropins. Sows (4 to 6/group) not returning to estrus by 42.8 +/- 3.1 days after weaning were assigned to 1 of the following treatments: 10 micrograms of estradiol benzoate (EB)/kg of body weight; 200 micrograms of GnRH, 1,000 IU of pregnant mare's serum gonadotropin (PMSG); 1,000 IU of human chorionic gonadotropin (HCG); or 4 ml of saline solution plus 2 ml of corn oil. A preovulatory-like surge of luteinizing hormone [(LH) greater than 12 hours in duration] was observed in all weaned sows treated with EB. All EB-treated sows exhibited estrus and ovulated but none conceived. Sows given GnRH had transiently increased (less than 3 hours) LH concentrations that were not associated with estrus or ovulation. Treatment with PMSG caused an increase in peripheral concentrations of 17 beta-estradiol that was followed by an LH surge, estrus, ovulation, and conception. Treatment with HCG caused an increase in circulating concentrations of 17 beta-estradiol that was accompanied by a surge of LH in some sows and ovulation in all sows. Not all sows treated with HCG exhibited estrous behavior, but conception occurred in 2 of 3 sows that were mated at estrus. None of the sows treated with saline plus corn oil had consistent changes in circulatory concentrations of 17 beta-estradiol or LH and none exhibited estrus or ovulated.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of zearalenone on days 7 to 10 postmating on intrauterine environment and migration of embryos in sows

On d 7 to 10 postmating, first-litter sows were fed either a control diet or a diet containing zearalenone (ZEN; 1 mg/kg body weight). Surgery was performed on either d 9, 11 or 13 postmating to collect blastocysts and uterine flushings. The rostral and caudal portion of each uterine horn was flushed with phosphate buffered saline, and the blastocysts were separated from the recovered solution. Uterine flushings were analyzed for total Ca, Mg, Zn, estradiol-17 beta (E2 17 beta) and progesterone (P4). Administration of ZEN did not affect the number of blastocysts recovered or the position of embryos within the uterus on d 9 or 11. Blastocysts recovered on d 13 were filamentous and could not be enumerated. Total Ca in uterine flushings of control sows was higher (P less than .001) on d 11 than on d 9 or 13, but intrauterine Ca of ZEN-treated sows did not vary by sampling day (P greater than .05) and was lower (P = .01) than that of controls on d 11. Total intrauterine Mg of ZEN sows was greater (P = .002) than of control sows on d 11 and 13, and total intrauterine Zn of ZEN sows was greater than that in control sows on d 13. There were no differences in total intrauterine P4 or E2 17 beta among ZEN-treated and control sows on d 9, 11 or 13 postmating. Serum concentrations of 13, 14-dihydro-15-ketoprostaglandin F2 alpha (PGFM) increased from d 9 to 13 in control and ZEN-treated sows, but there were no differences between treatment groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of catecholamines on the smooth muscles of the esophageal groove of calves

The effect of noradrenaline and adrenaline on isolated smooth muscle from the reticular groove of calves was studied. Both catecholamines caused a concentration-dependent (1.1.10(-6) mol/l) contraction of the transversal muscle strips from the floor of the reticular groove. This excitatory effect was antagonized by prazosin (10(-7)) mol/l), and by high concentrations of yohimbine (10(-6) mol/l) and atropine (10(-5)) mol/l). Tetrodotoxin (3.10(-6) mol/l), an inhibitor of nerve conduction, did not change the contraction induced by catecholamines (55.10(-6)) mol/l). Catecholamines did not produce a contraction of the longitudinal muscle from the lips of the reticular groove. The beta-adrenergic agonist isoprenaline (55.10(-6) mol/l) even elicited a reduction of acetylcholine (55.10(-6)) mol/l) induced contraction of both the transversal and the longitudinal muscle from the reticular groove. The relaxing effect of isoprenaline was antagonized by propranolol (55.10(-6)) mol/l). According to these results the excitatory effect of catecholamines on the smooth muscle cells occurs through alpha-adrenergic receptors, whereas the relaxing effect is mediated by beta-adrenergic receptors of the muscle cell. The excitatory effect of catecholamines on the transversal muscle appears to be predominant. Atropine appears to be an unspecific blocking agent of alpha-adrenergic receptors.