Oestrogen-dependent expression of LH/hCG receptors in pig Fallopian tube and their role in relaxation of the oviduct.
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The current studies investigated the concentration and distribution of LH receptors in the oviduct of ovariectomized gilts at various times after administration of oestradiol benzoate (10 micrograms kg-1 body weight) to determine whether LH participates in the regulation of oviductal contractions. Polyclonal antibodies to the LH receptor were used in immunocytochemical and western blot analyses of oviductal tissues. The mechanical activity of the isthmus and ampullar segments of oviduct, collected from 16 cyclic gilts, was recorded for 30 min after LH or hCG treatment. In the oviduct, there was little competition for receptor occupancy between hCG and pig FSH, bovine thyroid-stimulating hormone (TSH), pig growth hormone (GH) and pig prolactin (1.2, 0.1, 0.01 and < 0.001%, respectively) but pig LH could completely inhibit the binding of [125I]hCG. Oestradiol benzoate increased (P < 0.01) the number of LH binding sites in oviduct 24, 48 and 72 h (0.60 +/- 0.08, 1.62 +/- 0.15, 2.48 +/- 0.35 fmol mg-1 protein; n = 4 per treatment, respectively) after injection compared with the control gilts treated with corn oil (0.20 +/- 0.04 fmol mg-1 protein; n = 4). The affinity of oviductal LH/hCG binding sites (Ka) varied from 4.0 to 8.5 x 10(10) l mol-1 and was similar to that of luteal cell binding sites (6.1 x 10(10) l mol-1). Oestradiol benzoate also resulted in more intense LH receptor immunostaining of the tubal mucosal epithelium, smooth muscle cells and blood vessels as compared with controls. Western blotting has revealed that the pig oviduct, similar to the corpus luteum, contains 75, 48 and 45 kDa immunoreactive LH receptor proteins. Treatment with LH in vitro (100 ng ml-1) affected the contractility of oviduct. During the peri-ovulatory stage of the oestrous cycle, the amplitude, frequency and area under curve(s) of the isthmus decreased (P < 0.05), as did the frequency and area under curve (P < 0.05 and P < 0.01, respectively) of the ampulla (n = 4). The frequency and area under curve of the oviductal contractions were also significantly reduced during the early follicular phase of the oestrous cycle (P < 0.05). There was no effect of LH (or hCG) on the frequency and area under curve of the oviductal contractions during luteal stages of the oestrous cycle (n = 8). These data indicate that (1) the pig oviduct possesses immunoreactive and functional LH receptor, (2) oestradiol promotes the synthesis of LH receptor in the epithelium and smooth muscles, and (3) LH causes the relaxation of oviduct, especially during the peri-ovulatory stage of the oestrous cycle. In summary, the results of the present study indicate that LH can control oviductal contractions directly and may be partially responsible for the relaxation of isthmus during fertilization in pigs. (+info)
Antibody response to the chlamydial heat-shock protein 60 in an experimental model of chronic pelvic inflammatory disease in monkeys (Macaca nemestrina).
(26/1061)
A primate model of chlamydial pelvic inflammatory disease was used to characterize serum antibody responses to the 60 kDa chlamydial heat shock protein (CHSP60). Forty monkeys were infected in the fallopian tubes with Chlamydia trachomatis and then were treated. Twenty-three (58%) monkeys developed antibodies against CHSP60, of whom 6 (15%) had CHSP60 responses that persisted throughout the study and 17 (42.5%) had a transient response. A persistent CHSP60 antibody response was correlated with being culture- or ligase chain reaction-positive in the fallopian tubes (P=.004), but not in the cervix pretreatment, and with being tubal-positive posttreatment (P=. 02). Compared with tubal-negative monkeys, tubal-positive monkeys had more intense CHSP60 responses (P=.006) that lasted longer (P=. 002). Among CHSP60 responders, an OD>0.5 was correlated with more severe salpingeal pathology before treatment (P=.04). CHSP60 antibody response may be useful as a marker of persistent chlamydial infection in the fallopian tubes. (+info)
Inhalation of mainstream and sidestream cigarette smoke retards embryo transport and slows muscle contraction in oviducts of hamsters (Mesocricetus auratus).
(27/1061)
Prior experiments have shown that the functioning of hamster oviducts is impaired by in vitro exposure to cigarette smoke. To determine if cigarette smoke affects oviductal functioning in vivo, an inhalation experiment was done in which hamsters were exposed to doses of smoke similar to those received by human smokers. The effects of mainstream smoke (the bolus of smoke inhaled by active smokers) and sidestream smoke (the main component in environmental tobacco smoke) were compared. Transport of preimplantation embryos through the hamster oviduct was retarded in females inhaling doses of mainstream or sidestream smoke that produced serum cotinine levels within the range reported for women who actively or passively smoke during pregnancy. In addition, hamster oviductal muscle contraction rate decreased significantly during a single exposure of animals to either mainstream or sidestream smoke, and contraction rate failed to return to initial control values during a 25-min recovery period. Both preimplantation embryo transport and muscle contraction were more sensitive to sidestream than mainstream smoke. These data demonstrate that inhalation of doses of mainstream and sidestream cigarette similar to those received by active and passive human smokers adversely affects functioning of the oviduct and may explain the increased incidence of ectopic pregnancies reported in women who smoke. (+info)
Effect of inflammatory mediators on the electrophysiology of the human oviduct.
(28/1061)
The effects of histamine and other inflammatory mediators on the electrophysiology and intracellular free calcium ([Ca(2+)](i)) of human oviductal epithelial cells, grown as a polarized layer in primary culture, were studied. Transepithelial potential difference (PD) and short-circuit current (I(scc)) were recorded using a modified Ussing chamber. Resistance (R) was calculated from the measurements of PD and I(scc). Basally applied histamine produced transient increases in PD and I(scc) with a small decrease in R. The histamine effect was reduced by triprolidine (H(1) receptor antagonist) but was unaffected by H(2) (ranitidine) or H(3) (thioperamide) receptor antagonists. Blockers of Na(+), K(+), or Na(+)/K(+)/2Cl(-) channels did not affect histamine action. Blockers of Cl(-)/HCO(3)(-) channels or Ca(2+) channels reduced the histamine effect. Platelet activating factor (PAF), applied apically, increased PD and I(scc). Histamine produced a transient increase in fluorescence of Fura 2-AM dye, indicating an increase in [Ca(2+)](i). Triprolidine pretreatment inhibited histamine-stimulated [Ca(2+)](i) increase. Cimetidine, (H(2) receptor antagonist), ranitidine, or thioperamide reduced the histamine effect. Histamine increased contractions of both circular and longitudinal smooth muscles in oviduct segments, an effect that was antagonized by triprolidine or thioperamide but not by ranitidine. Histamine's action on Ca(2+) and Cl(-) movements may adversely affect oviductal fluid production and decrease fertility. PAF's effects on Cl(-) movements may be important for normal embryo transport. (+info)
Fimbrial capture of the ovum and tubal transport of the ovum in the rabbit, with emphasis on the effects of beta 2-adrenoreceptor stimulant and prostaglandin F2 alpha on the intraluminal pressures of the tubal ampullae.
(29/1061)
PURPOSE: Our purpose was to elucidate the roles of the ampullar and isthmic portions of the oviduct and the effects of drugs on oviductal contractility. METHODS: Prostaglandin F2 alpha (PGF2 alpha; Ono Pharmaceuticals, Osaka) and oxytocin (Atonin-O; Teikoku Hormone Manufacturing Co. Ltd., Tokyo) were used to stimulate oviductal contractility, and ritodrine hydrochloride (Utemerin; Solvay-Duphar Corp., Denmark) to inhibit the contractility. RESULTS: Both PGF2 alpha and Atonin-O were involved in ovum capture by the ampullar oviduct by stimulating contractility, thus altering the intraductal pressures. Utemerin is effective in inhibiting the enhanced contractility induced by PGF2 alpha and Atonin-O. CONCLUSIONS: Variations in pressure of the ampullar portion of the oviduct seem necessary for the capture of ova expelled from the ovary. Once in the isthmic portion of the oviduct, transport appears to be under the influence of ciliary activity rather than variations in contractility. (+info)
Carbohydrate-based interactions on the route of a spermatozoon to fertilization.
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Male and female intercommunication along the route which the spermatozoon takes to fertilization utilizes the information potential of carbohydrates. A hierarchy of carbohydrate-based binding events exists ranging from spermatozoa-oviduct interaction to primary and secondary binding between spermatozoon and oocyte. Before in-vivo fertilization can occur, spermatozoa are stored in the caudal part of the isthmus, in tight contact with the epithelium cells lining the oviduct. The sperm reservoir seems to be created by surface-associated sperm lectins recognizing epithelial glycoconjugates. With the changing conditions in the oviduct at the time of ovulation, spermatozoa may shed those sperm lectins, creating new surfaces which allow spermatozoa to be released from the epithelium, complete capacitation and interact with the oocyte in the appropriate manner. The first contact between both gametes occurs at the spermatozoa-zona pellucida interface. The 'primary' binding initiates the acrosomal exocytosis of the spermatozoa, followed by the 'secondary' binding of the acrosome-reacted spermatozoon that in consequence leads to sperm penetration through the zona pellucida. Primary and secondary binding events are directed by the cooperative interactions of multiple carbohydrate-recognition systems that may act in a hierarchical and redundant manner. The current perspective will focus on the role of carbohydrate-binding sperm proteins in the sequence of binding events during fertilization in the pig. (+info)
Effects of hydrosalpingeal fluid on murine embryo development and implantation.
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PURPOSE: Our purpose was to evaluate the effects of various concentrations of hydrosalpingeal fluid (HSF) on the preimplantation development and implantation of murine embryos. METHODS: One-cell mouse embryos were cultured in KSOM culture medium with 0.1, 1.0, 10, or 50% HSF, without and with lactate supplementation. Late-stage embryos were transferred into the uteri of pseudopregnant CD-1 females to determine implantation rates. The embryo transfer technique used was developed by our group and its effectiveness was evaluated during this experiment. RESULTS: Blastocyst development in the 0.1, 1.0, 10, and 50% group was 45, 55.0, 12.5, and 17.5%, respectively, with lactate supplementation, and 35.0, 52.5, 12.5, and 5.0%, respectively, without lactate supplementation, while in the KSOM (control) group it was 63.8%. Blastocyst development was reduced compared to controls in the 10% HSF and 50% HSF groups. Implantation rates for the 0.1 and 1.0% groups with lactate supplementation were 43.0 and 25.0%, respectively, and those with lactate supplementation were 50.6 and 61.8%, respectively, while in the KSOM group the implantation rate was 65.5%. None of the implantation rates were significantly different. CONCLUSIONS: Hydrosalpingeal fluid has a concentration-dependent inhibitory effect on in vitro murine embryo development, but it has minimal effects on implantation rates. (+info)
Influence of inhibitors on increase in intracellular free calcium and proliferation induced by platelet-activating factor in bovine oviductal cells.
(32/1061)
Oviductal endosalpingeal cells were isolated mechanically from heifers and cultured until there was 100% confluency. The cells were loaded with the Ca(2+)-sensitive fluorochrome, fura-2/acetoxymethylester, and cytosolic free calcium ([Ca2+]i) was monitored by spectrofluorimetry. Platelet-activating factor, at a concentration of 30 nmol l-1, induced an intracellular Ca2+ increase in cultured bovine oviductal cells, mainly via influx from the extracellular space. In fura-2-loaded oviductal cells, different Ca2+ channel blockers were investigated to characterize the pathways responsible for the Ca2+ influx. The negative effects of Ni(2+)-, La(3+)-activated K+ channel blockers, such as apamin and charybdotoxin, and Ca2+ channel blockers, such as dotarizine, on the platelet-activating factor-induced [Ca2+]i increase indicate the minor participation of the voltage-gated Ca2+ channels. TMB-8 and flufenamic acid blocked the platelet-activating factor-induced Ca2+ increase directly on non-selective cationic channels or acted via a Ca2+ release-triggered Ca2+ influx. Platelet-activating factor, at concentrations of 1.25 mumol l-1 and 2.5 mumol l-1, significantly stimulated the proliferation and depolarization of oviductal cells, but 10 mumol l-1 significantly decreased both parameters and exerted a cytotoxic effect on cells. After incubation with TMB-8 or flufenamic acid, the cell proliferation was inhibited in a concentration-dependent manner, with IC50 values of 26.57 mumol l-1 and 95.29 mumol l-1, respectively. The depolarization was significantly inhibited at 50 mumol l-1 for both TMB-8 and flufenamic acid. The results of the present study may contribute to further understanding of the mechanism behind the actions of platelet-activating factor on oviductal cells. (+info)