Tumour necrosis factor-α is the signal induced by mating to shutdown a 2-methoxyestradiol nongenomic action necessary to accelerate oviductal egg transport in the rat.

Mating shut down a 2-methoxyestradiol (2ME) nongenomic action necessary to accelerate egg transport in the rat oviduct. Herein, we investigated whether tumour necrosis factor-α (TNF-α) participates in this mating effect. In unmated and mated rats, we determined the concentration of TNF-α in the oviductal fluid and the level of the mRNA for Tnf-a (Tnf) and their receptors Tnfrsf1a and Tnfrsf1b in the oviduct tissues. The distribution of the TNFRSF1A and TNFRSF1B proteins in the oviduct of unmated and mated was also assessed. Finally, we examined whether 2ME accelerates oviductal egg transport in unmated rats that were previously treated with a rat recombinant TNF-α alone or concomitant with a selective inhibitor of the NF-κB activity. Mating increased TNF-α in the oviductal fluid, but Tnf transcript was not detected in the oviduct. The mRNA for TNF-α receptors as well as their distribution was not affected by mating, although they were mainly localized in the endosalpinx. Administration of TNF-α into the oviduct of unmated rats prevented the effect of 2ME on egg transport. However, the NF-κB activity inhibitor did not revert this effect of TNF-α. These results indicate that mating increased TNF-α in the oviductal fluid, although this not associated with changes in the expression and localization of TNF-α receptors in the oviductal cells. Furthermore, TNF-α mimicked the effect of mating on the 2ME-induced egg transport acceleration, independently of the activation of NF-κB in the oviduct. We concluded that TNF-α is the signal induced by mating to shut down a 2ME nongenomic action in the rat oviduct.

[Follicular fluid in mammals]. / Le liquide folliculaire chez les mammifères.

Follicular fluid is a complex extracellular fluid, semi-viscous and yellow in colour, which accumulates in the antrum of ovarian follicles during their growing phase. Follicular fluid provides the microenvironment within which the cumulus-oocyte complex matures and granulosa cells differentiate. Scientists agree that follicular fluid derives mainly from plasma via the vascular compartment in the follicle wall. However, it also contains factors produced locally by the follicle cells, the production of which varies during different reproductive states. The aim of this paper is to review current knowledge on the formation, composition and roles of follicular fluid.

Ciliary transport, gamete interaction, and effects of the early embryo in the oviduct: ex vivo analyses using a new digital videomicroscopic system in the cow.

Using a digital videomicroscopic analysis system in the bovine, we showed that the mechanisms of transport caused by ciliary beating are distinctly different in ampulla and isthmus of the oviduct. The average particle transport speed (PTS) in the oviduct (mean, 133 microm/sec) does not differ in the cycle (metestrus) and during pregnancy after implantation, but it is locally modulated at the site of the embryo. Using videomicroscopy, we were able to document that after entering the ampulla, the cumulus-oocyte complex (COC) is not transported by ciliary beating down the oviduct, but firmly attaches to the ampullar epithelium. This attachment is mediated by the cumulus cells. However, when a COC is degenerated, it is floating in the oviductal lumen. As soon as a vital COC is in the ampulla, the sperm bound in the sperm reservoir of the ampullar isthmic junction leave the reservoir and hurry to the oocyte. When a sperm has penetrated the zona pellucida, the COC detaches and continues its migration. Quantitative measurements showed that the early embryo is able to locally downregulate PTS during its migration down the oviduct. It locally changes the pattern of vascularization and induces the formation of secretory cells. Our studies imply that the oviductal epithelium is able to select vital oocytes. The early embryo is able to induce the formation of secretory cells, modify vascularization, and downregulate speed of transport, thus creating the prerequisite for the first embryo-maternal communication in the oviduct.

Endothelin-2 induces oviductal contraction via endothelin receptor subtype A in rats.

Proper function of the oviduct is critical to reproductive success with regulated contraction and relaxation facilitating transportation of the germ cells to the site of fertilization. Endothelin-2 (EDN2) is a potent vasoconstrictor produced by granulosa cells of the preovulatory follicle at the time of ovulation; however, whether this gonadotropin surge-induced peptide played a role in facilitating germ cell transportation by inducing oviductal contraction was unknown. The objectives of these experiments were (1) to determine whether the endothelin receptor system was present in the oviduct, (2) to test the hypothesis that EDN2 induces oviductal contraction via a specific endothelin receptor subtype, (3) to determine, as a possible alternate source of the ligand, whether mRNA for EDN2 was expressed in cumulus-oocyte complexes (COCs) within the oviduct, and (4) to determine whether EDN2 could overcome prostaglandin E(2) (PGE(2))-induced oviductal relaxation. Microarray and real-time PCR analysis indicated that mRNA for both the endothelin receptor subtypes (ET(A) and ET(B)) was present in the oviduct, whereas immunohistochemical examination revealed that ET(A) protein was the dominant isoform, present in the luminal epithelial cells of the oviduct. Real-time PCR analysis demonstrated that mRNA for EDN2 was expressed in COCs after ovulation. Isometric tension analysis indicated that EDN2 was a potent oviductal constrictor and that the contractile effect of EDN2 was mediated by the ET(A) and not the ET(B) receptor subtype. The oviductal contraction induced by EDN2 also reversed oviductal relaxation induced by PGE(2). In summary, ET(A) receptor-specific EDN2-induced contraction as a facilitator of oviductal function suggests a novel pathway involved in germ cell transport and hence mammalian fertility.

Inositol triphosphate participates in an oestradiol nongenomic signalling pathway involved in accelerated oviductal transport in cycling rats.

Oestradiol (E(2)) accelerates oviductal transport of oocytes in cycling rats through a nongenomic pathway that involves the cAMP-PKA signalling cascade. Here we examined the role of the inositol triphosphate (IP3) and mitogen-activated protein kinase (MAPK) signalling cascades in this nongenomic pathway. Oestrous rats were injected with E(2) s.c. and intrabursally (i.b) with the selective inhibitors of phospholipase C (PLC) ET-18-OCH(3) or MAPK PD98059. The number of eggs in the oviduct assessed 24 h later showed that ET-18-OCH(3) blocked E(2)-induced egg transport acceleration, whereas PD98059 had no effect. Other oestrous rats were treated with E(2) s.c. and 1, 3 or 6 h later oviducts were excised and the levels of IP3 and phosphorylated MAPK p44/42 (activated) were determined by radioreceptor assay and western blot, respectively. Oestradiol administration increased IP3 level at 1 and 6 h after treatment, whereas activated MAPK p44/42 level was unchanged. Finally, we explored whether cAMP-PKA and PLC-IP3 signalling cascades are coupled. Inhibition of adenylyl cyclase by i.b. injection of SQ 22536 blocked the increase of IP3 levels induced by E(2), while inhibition of PLC by ET-18-OCH(3) had no effect on E(2)-induced PKA activity. Furthermore, activation of adenylyl cyclase by Forskolin increased oviductal IP3 levels. Thus, activation of PLC-IP3 by E(2) requires previous stimulation of cAMP-PKA. We conclude that the nongenomic pathway utilised by E(2) to accelerate oviductal transport of oocytes in cycling rats involves successive activation of the cAMP-PKA and PLC-IP3 signalling cascades and does not require activation of MAPK. These findings clearly illustrate a non-genomic pathway triggered by E(2) that regulates a complex physiologic process accomplished by an entire organ.

Diminished pregnancy rates in endometriosis due to impaired uterotubal transport assessed by hysterosalpingoscintigraphy.

OBJECTIVE: To investigate uterotubal transport by means of hysterosalpingoscintigraphy (HSSG) in women with and without endometriosis. DESIGN: A prospective observational study. SETTING: University Hospital, Department of Obstetrics and Gynaecology, Division of Reproductive Medicine and Gynaecologic Endocrinology with 350 in vitro fertilisation (IVF)/intracytoplasmic sperm injection (ICSI) cycles and 400 intrauterine insemination (IUI) cycles/year. POPULATION: Cases included 56 infertile women with laparoscopic proven endometriosis and patent fallopian tubes. Twenty-two women with partners suffering from male factor infertility served as controls. METHODS: A diagnostic cycle incorporating HSSG was performed. Subsequently, patients underwent either four cycles of timed intercourse (TI) or IUI in order to achieve pregnancy. If pregnancy did not occur, IVF or ICSI was performed. MAIN OUTCOME MEASURES: Evaluation of uterotubal transport capacity in women with endometriosis and healthy controls. RESULTS: Patients suffering from endometriosis (group I) showed a significant reduction in physiologic uterotubal transport function: While 20 patients (36%) had ipsi- or bilateral uterotubal transport, there was pathological uterotubal transport contralateral to the dominant follicle or a complete failure of transport capacity (negative HSSG) in 36 patients (64%). In the controls (group II), transport function was significantly different: 15 of 22 patients (68%) revealed ipsi- and bilateral tubal demonstration, while 5 patients (22%) showed contralateral transport and 2 patients (10%) showed negative HSSG (P= 0.01). Twenty-three pregnancies were observed (pregnancy rate: 29%). Eleven out of 14 (79%) women with ipsi- or bilateral tubal transport function fell pregnant by means of TI or IUI. In seven of nine patients (78%) with a failure in tubal transport, pregnancy was achieved by IVF/ICSI, despite acceptable semen parameters (P= 0.01). CONCLUSIONS: Endometriosis is significantly associated with a reduction in physiologic uterotubal transport capacity compared with controls. This resulted in diminished pregnancy rates even in women with normozoospermic partners. Therefore, IVF/ICSI may be required even when fallopian tubes are patent or semen quality is normal.

Oviduct contractile response to vaginal distension: identification of vagino-tubal reflex.

OBJECTIVE: The effect of vaginal distension on the oviduct contractile activity during penile thrusting at coitus could not be traced in the literature. We investigated the hypothesis that vaginal distension effects oviduct contraction, which assists in ovum transport along the oviduct. METHODS: Oviduct pressure was measured upon vaginal condom distension in 16 women (mean age 32.2+/-1.2 years) scheduled for abdominal hernia repair and oviduct ligation for sterilization. The test was repeated after individual anesthetization of the vagina and oviduct. RESULTS: Ten milliliters vaginal distension effected pressure elevation of the ampullary (AO) and isthmic (IO) parts of the oviduct (p<0.01, p<0.01 respectively) and a decrease in intramural oviduct (IMO; p<0.01). Twenty milliliters distension further increased the pressure in the AO and the IO (p<0.001, p<0.001) and decreased it in IMO (p<0.001). Vaginal distension with greater volumes produced an oviduct pressure response similar to that with 20 ml distension (p>0.05). Vaginal distension of anesthetized vagina or oviduct did not evoke the oviduct pressure response, but saline infusion did. CONCLUSIONS: Vaginal distension seems to produce oviduct motile activity as evidenced by oviduct pressure changes, which appear to assist in sperm-ovum transport and fertilization. These oviduct changes are suggested to occur reflexly through the "vagino-tubal reflex." Pathologic changes of the oviduct presumably interfere with this reflex action, a point that needs to be investigated.

Aberrant cannabinoid signaling impairs oviductal transport of embryos.

Ectopic pregnancy is a major reproductive health issue. Although other underlying causes remain largely unknown, one cause of ectopic pregnancy is embryo retention in the fallopian tube. Here we show that genetic or pharmacologic silencing of cannabinoid receptor CB1 causes retention of a large number of embryos in the mouse oviduct, eventually leading to pregnancy failure. This is reversed by isoproterenol, a beta-adrenergic receptor agonist. Impaired oviductal embryo transport is also observed in wild-type mice treated with methanandamide. Collectively, the results suggest that aberrant cannabinoid signaling impedes coordinated oviductal smooth muscle contraction and relaxation crucial to normal oviductal embryo transport. Colocalization of CB1 and beta2-adrenergic receptors in the oviduct muscularis implies that a basal endocannabinoid tone in collaboration with adrenergic receptors coordinates oviductal motility for normal journey of embryos into the uterus. Besides uncovering a new regulatory mechanism, this study could be clinically relevant to ectopic pregnancy.

Postovulatory effect of intravenous administration of lipopolysaccharide (E. coli, O55:B5) on the contractile activity of the oviduct, ova transport, binding of accessory spermatozoa to the zona pellucida and embryo development in sows.

The effect of lipopolysaccharide (LPS) (E. coli, O55:B5), administered 18 h after ovulation in the second oestrus after weaning, on the contractile activity of the oviduct, ova transport, sperm binding to zona pellucida (ZP) and embryo development, was studied in 14 Swedish crossbred (Landrace Yorkshire) multiparous sows. The endotoxin group (E-group) sows were administered with 300 ng/kg of LPS while the control group (C-group) sows were administered with 5 ml of saline i.v. via an indwelling jugular cannula. Immediately after evidence of standing oestrus, a Millar pressure transducer was placed intraluminally about 3 cm into the mid-isthmus, via laparotomy. Pressure recordings of the oviduct were collected from all conscious sows until slaughter. After slaughter, the genital tract opposite to the side with the transducer was retrieved, and three equal isthmic segments and the first third of the uterine horn part adjacent to the utero-tubal-junction (UTJ) were flushed separately to recover the ova. The intervals (mean+/-SD) from ovulation to slaughter (OS) and insemination to ovulation (IO) were not different between the E-group (44.5 +/- 5.7 h; 13.3 +/- 6.5 h) and the C-group (42.7 +/- 5.9 h; 14.8 +/- 4.1 h), respectively. Ova recovery rate (RR) in the E-group (80.2 +/- 22.9%) did not differ from that in the C-group (85.2 +/- 4.5%). The frequency distribution of ova recovered in the different segments did not significantly (p > 0.05) differ between the groups. The E-group showed higher cleavage rate than controls. A higher proportion of spermatozoa bound to the ZP was also found in the E-group compared with controls. The isthmic intraluminal pressure slightly increased (p = 0.07) 18 h after ovulation and immediately following LPS in the E-group, compared with the C-group. The frequencies of phasic pressure fluctuations were significantly (p < 0.05) lower at 30 and 38 h after ovulation in the E- than in the C-group. It can be concluded from the present study that a single i.v. administration of LPS (300 ng/kg body weight) to sows, 18 h after ovulation might be associated with changes in isthmic pressure and the frequency of phasic pressure fluctuations, increased numbers of spermatozoa attached to the ZP and an enhanced embryo development but not with ova transport rates.

Transport of fertilised and unfertilized ova in sows.

Transport of fertilised and unfertilized ova was studied in 22 crossbred (Landrace x Yorkshire) multiparous sows. Sows in the inseminated group (I-group, n=11) were inseminated once with 100ml of BTS extended semen from two fertile boars with a total of 10 x 10 (9) spermatozoa during the second oestrus after weaning between 18 and 8h prior to estimated time of ovulation, as estimated from the first oestrus after weaning. All the sows were slaughtered between 36 and 48 h after ovulation in the second oestrus after weaning by stunning and bleeding. After slaughter, the reproductive tract was immediately recovered, the isthmus was divided into three equal segments, and the number of ova was determined in each segment and in the upper third of the uterine horn from the UTJ. There were no significant differences (P>0.05) either in the intervals from ovulation to slaughter (42.3+/-6.2h versus 43.2+/-5.4h) or in the numbers of corpora lutea (CL) (18.2+/-5.5 versus 15.9+/-3.5) between the non-inseminated (N-group) and the inseminated groups (I-group), respectively. Ova recovery rate was 92.5% in the N-group and 82.9% in the I-group (P>0.05). In the I-group, ova had passed 2.2+/-0.3 segments whereas in the N-group, ova had passed 2.6+/-0.3 segments (P=0.38). It can be concluded that there is no difference in the transportation of either fertilised or unfertilized ova in the reproductive tract of pigs.

Impact of postovulatory food deprivation on the ova transport, hormonal profiles and metabolic changes in sows.

The effect of food deprivation on ova transport, hormonal profiles and metabolic changes was studied in 20 crossbred multiparous sows during their second oestrus after weaning. To determine the time of ovulation, transrectal ultrasonographic examination was performed. The sows were divided into 2 groups, one control group (C-group), which was fed according to Swedish standards, and one experimental group (E-group). The E-group sows were deprived of food from the first morning meal after ovulation until slaughter. Blood samples were collected every second hour from about 12 h before expected ovulation in the second oestrus after weaning until slaughter and were analysed for progesterone, prostaglandin F2 alpha-metabolite, insulin, glucose, free fatty acids and triglycerides. All sows were slaughtered approximately 48 h after ovulation and the genital tract was recovered. The isthmic part of the oviduct was divided into 3 equally long segments and flushed separately with phosphate buffered saline (PBS). Uterine horns were also flushed with PBS. A significantly greater number of ova were found in the first and second part of the isthmus in the E-group (p = 0.05) while in the C-group most of the ova were found in the third part of the isthmus or the uterus (p = 0.01). The level of prostaglandin F2 alpha-metabolite was significantly higher in the E-group compared with the C-group. The concentration of progesterone increased in both groups after ovulation but there were no significant differences between the groups. The other blood parameters showed that the food-deprived sows were in a catabolic state. The 48 h period of fasting results, directly or indirectly in an delayed ova transport, which may be due to a delayed relaxation in the smooth circular muscle layer of the isthmus.

Ovulation triggers activation of Drosophila oocytes.

Drosophila melanogaster mature oocytes in ovaries are arrested at metaphase I of meiosis. Eggs that have reached the uterus have released this arrest. It was not known where in the female reproductive tract egg activation occurs and what triggers it. We investigated when and where the egg is activated in Drosophila in vivo and at what meiotic stage the egg is fertilized. We found that changes in the egg's envelope's permeability, one feature of activation, initiate during ovulation, even while most of the egg is still within the ovary. The egg becomes impermeable as it proceeds down the oviducts; the process is complete by the time the egg is in the uterus. Cross-linking of vitelline membrane protein sV23 also increases progressively as the egg moves through the oviducts and the uterus. Activation also triggers meiosis to resume before the egg reaches the uterus, such that the earliest eggs that reach the uterus are in anaphase I. We discuss models for Drosophila egg activation in vivo.

Effects of post-ovulatory food deprivation on the hormonal profiles, activity of the oviduct and ova transport in sows.

The objective of the present study was to investigate the effect of post-ovulatory food deprivation on the hormonal profiles and consequently on the activity of the oviduct and ova transport in sows. Sows were randomly allocated to the control (C-group, n=6) or fasted (F-group, n=5) group. The F-group sows were fasted for four meals starting with the morning meal after detection of ovulation in the second oestrus after weaning. Ovulation was checked by transrectal ultrasonography. Blood was collected for the analyses of progesterone, oestradiol-17beta, prostaglandin F(2 approximately ) metabolite, insulin, free fatty acids and triglycerides. Oviductal isthmic motility was monitored on Polyview before and after ovulation until the time of slaughter. After slaughter, the isthmus opposite the side with transducer was divided into three equal segments and flushed separately and a third of the uterine horn part from the utero-tubal-junction (UTJ) was also flushed. A high proportion of ova in the F-group was found in the first and second parts of the isthmus. In the C-group, a high proportion of ova was found in the third part of the isthmus and the uterus. The mean isthmic pressure in the C-group decreased significantly (P<0.05) during the period immediately after ovulation while in the F-group mean pressure remained unchanged. The frequency of phasic pressure fluctuations were significantly (P<0.05) higher in the F- than in the C-group 13 to 24 h after ovulation. No significant differences in progesterone concentrations were seen between the two groups of sows. Prostaglandin metabolite levels were significantly (P<0.05) higher in the F-group than in the C-group. Oestradiol-17beta levels significantly (p<0.05) decreased earlier in the F- than in the C-group. Serum insulin levels were significantly (p=0.05) lower in the F- than in the C-group while free fatty acids were significantly (p<0.01) higher in the F- than in the C-group. There were no significant differences in the serum levels of triglycerides between the F- and the C-group. Therefore, it can be concluded in the present study that food deprivation is associated with changes in the hormonal profiles, activity of the oviduct and a delay of ova transport in sows.

Relationship between changes in volume of the oviductal fluid in the ampulla and the descent of ovulated eggs from the ampulla to the isthmus in mice.

Follicular growth and ovulation were induced in mice by administration of pregnant mare serum gonadotrophin (PMSG) followed 2 days later by human chorionic gonadotrophin; the day of PMSG injection was designated as day 0. The volume of the ampulla was measured and the location of the ovulated eggs determined at 06:00, 10:00, 14:00, 18:00 and 22:00 on day 3, and at 02:00 and 06:00 on day 4. The volume of the ampulla and hence oviductal fluid, peaked at 14:00 on day 3 and then declined. In all oviduct samples taken up to 14:00 on day 3, eggs were found exclusively in the ampulla. Thereafter, an increasing number of eggs were observed in the isthmus. Thus, the migration of eggs from the ampulla to the isthmus was concurrent with the decrease in oviductal fluid volume. The peak in the volume of oviductal fluid seen at day 3 is likely to coincide with the opening of the ampullary-isthmic junction of the oviduct.

In vitro analysis of oocyte cumulus complex pickup rate in the hamster Mesocricetus auratus.

In mammals, the oocyte and its surrounding cumulus cells constitute on oocyte cumulus complex (OCC). During ovulation, OCCs are extruded into the peritoneal or bursal cavity, depending on the species, and are then rapidly picked up by the fimbria on the outer surface of the oviductal infundibulum and transported to the ampulla, where fertilization occurs. We developed a method to measure OCC pickup rates quantitatively in vitro, and we used this method to evaluate the effects of viscosity and temperature on pickup rates. Hamster infundibula are placed in a holding pipette in a chamber modified to study OCC pickup. Ciliary beat frequencies (CBF) can be measured in the same preparation. Pickup rates vary depending on the pathway on which the OCC travels over the surface of the infundibulum; however, rates for a given pathway are very consistent. The average pickup rate at room temperature calculated from three different pathways/infundibulum was 55.2 +/- 10.6 microns/sec. Both rates between infundibula from the same female and rates among infundibula from different females were in most cases similar. Preparations preincubated in vitro for 2.75 hr produced rates similar to nonpreincubated samples, while longer preincubation resulted in decreased rates. Inclusion of Ficoll in culture medium to increase viscosity caused a concentration-dependent decrease in both OCC pickup rate and in CBF. However, a significant decrease in OCC pickup rate was only observed at viscosities higher than those found in bursal fluid. When trials were run at physiological temperature (36.4 degrees C) rather ambient temperature, rates increased to 136.7 +/- 29.9 (SD) microns/sec. Linear regression analysis demonstrated a strong positive correlation (r = 0.94) between OCC pickup rate and temperature. The OCC pickup rate assay can be used experimentally, and should be valuable in evaluating factors that affect rate and in studies dealing with the mechanism of OCC pickup.

Influence of prostaglandins E2 and F2 alpha on passage pressure across the uterotubal junction and isthmus in the rat.

The influence of prostaglandins E2 and F2 alpha on passage pressure across the uterotubal junction (UTJ) and isthmus were studied in rats that were either in the pro-oestrus, oestrus, metoestrus or dioestrus phases. Effects of these prostaglandins were also investigated in rats that had been either ovariectomized and treated with oestradiol or medroxiprogesterone acetate, or only ovariectomized. In each rat, the left UTJ was surgically resected and the isthmus anastomosed to the uterine horn, whereas the right UTJ was left untouched. The passage pressures across the left isthmus and the right UTJ were measured before and after prostaglandin treatment. The pressures obtained in the UTJ in the oestrus phase and oestrogen-treated ovariectomized animals were lower than those registered in the remaining groups. Prostaglandin E2 decreased the pressures when compared with pre-treatment measures in all groups. Significantly higher pressures were registered across the UTJ in prostaglandin F2 alpha than in E2 treatment, with these higher pressures being similar to pre-treatment pressures. Both hormonal changes throughout the oestrous cycle and prostaglandin E2 treatment had a similar influence on the passage pressure across the isthmus, as that described for UTJ, but with lower values. The results indicate that prostaglandin E2 decreases the passage pressure across both UTJ and isthmus and can have an influence on the regulation of transport across these 2 areas.

Oviductal function is critical for very early human life.

For normal fertilization, the ovum must be picked up from the ovarian surface or from the abdominal cavity into the ampulla. The rapid transport of gametes includes a complex reorganization of the oviductal smooth muscle electrical activity that precedes the mechanical activity. The 3-day stay at the ampulla-isthmic junction requires both signals from the ovum to the oviduct and vice versa, supporting the ovum and regulating its to-and-fro movements. Oviductal fluid, a principal factor in tubal function, coats the newly fertilized egg, activates transcription and gives a signal for sperm fertility potential. Early blocks to embryo development in in vitro conditions, as compared to in vivo success, means that critical developments during the first cell cycles of embryonic life in the oviduct are actively regulated by oviductal embryotrophic factors. These have been used clinically in co-culture systems. Lytic factors are weak in human and other primates, predisposing to high incidence of tubal pregnancies, with considerable impact on medical practice. Diverse oviductal factors affect the incidence, infection being the most significant. Optimal oviductal function is necessary to provide a proper environment for early human life.

Possible role of platelet-activating factor in embryonic signaling during oviductal transport in the hamster.

Hamster embryos enter the uterus in pregnant females nearly one day earlier than unfertilized eggs in cycling females. The hypothesis that a substance derived from eicosanoids is released by the embryos, but not by oocytes, to hasten their transport to the uterus was tested by examining the effects of indomethacin, nordihydroguaiaretic acid (NDGA), platelet-activating factor (PAF), and PAF antagonists on egg transport in the hamster. Administration of indomethacin had no effect on embryo transport, whereas administration of NDGA delayed the transport of eggs to the uterus in pregnant but not in cycling hamsters. The PAF antagonists TCV-309 and BN-52021 delayed significantly the transport of eggs to the uterus in pregnant animals, but not in cycling animals; i.e., they retarded the passage of embryos but not of oocytes to the uterus. Administration of PAF to cycling hamsters hastened the oviductal transport of ova. These data suggest that, in the hamster, the earlier passage of embryos to the uterus as compared to oocytes is mediated by PAF. Thrombocytopenia was detected in early-pregnant hamsters, and PAF-like activity was detected in spent media of two-cell through morula stage hamster embryos. These results suggest that preimplantation hamster embryos produce PAF-like activity that mediates embryonic signaling to the oviduct as well as pregnancy-associated thrombocytopenia.

Structural changes in the oviductal wall during the passage of unfertilized cumulus-oocyte complexes in mice.

BACKGROUND: Little information is available on the structural relationship of cumulus-oocyte complexes and the oviductal wall during the transport of cumulus-oocyte complexes. Then, morphological changes of the oviductal wall during the passage of unfertilized cumulus-oocyte complexes was examined chronologically in ICR mice 25-27 days of age injected with PMSG and hCG. METHODS: Mice were sacrificed at 12, 14, 16, 18, and 24 hr after the injection of hCG to remove oviducts, and the height of mucosal folds, muscle layers, and epithelial cells were measured in the serial sections stained with hematoxylin-eosin or colloidal iron. RESULTS: The height of the mucosal fold and muscle layer where cumulus-oocyte complexes were located was less than that of the adjacent portions. At 12-18 hr of hCG injection (about 2-8 hr after ovulation), the ova with surrounding cumulus cells lie free in a wide lumen, and the muscular tissue consists of only 2 or 3 layers of cells, arranged mostly longitudinally. However, a neighboring portion without cumulus-oocyte complexes, where the folds meet in the middle, appreciably restricts the free space in the lumen. After 24 hr of hCG administration, structural changes in the oviductal wall, where cumulus-oocyte complexes were located, were no longer apparent. The number of cumulus cells surrounding the oocyte decreased during the passage through the oviduct. At 12-18 hr after hCG injection, about 140 cells were identified in the largest cross section of a cumulus-oocyte complex, but, after 24 hr of hCG administration (about 14 hr after ovulation), an oocyte was surrounded with only about 25 cells. CONCLUSIONS: These results indicate that oocyte-cumulus cell complexes influence the structure of the oviductal wall during the passage in the oviduct.