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PubMed1989

[Study on follicle growth, ovulation and morphological changes of endometrium by ultrasonic and biochemical measurements].

Daily growth of the follicles before ovulation and the changes of the endometrium after ovulation were recorded in 16 spontaneous menstrual cycles by the ultrasonic and biochemical measurements. The mean diameter of the dominant follicle was 20 mm before ovulation, the mean volume 3.0 ml, and the growth rate of the follicles 1-3 mm/24 h. Ovulation occurred within 24 h of the luteinizing hormone peak and within 48 hours of the blood estrogen peak. The fact that the blood progesterone levels were higher on the day of the LH peak indicated that luteinization of the dominant follicles had already occurred prior to ovulation. Sonographic criteria of the endometrical tissue were obtained after the serial observation. According to the different sonographic appearances, the secretory phase of the endometrial tissue was divided into the early secretory phase, the middle secretory phase and the late secretory phase. The sonographic characterization of the endometrial tissue in the different phases as well as the thickness of the endometrium during the cycles were described. The clinical usefulness of the criteria of the different phases was to evaluate the subsequent luteal function, and facilitate the clinical management of the infertile women. The study confirms that ultrasound can provide a reliable measure in monitoring the follicular growth and ovulation, and observing the morphological changes of the endometrial tissue during the secretory phase. Thus the in vivo differentiation of the endometrial tissue during the secretory phase could be studied non-invasively by means of the ultrasound tissue characterization.

Adult↗
PubMed1987

[Ovulation induction with a combination of LHRH analogue and hMG pulsatile subcutaneous administration in PCO patients].

The pulsatile subcutaneous administration of hMG (hMG therapy) and treatment with a combination of luteinizing hormone releasing hormone analogue (Buserelin) and hMG (combined therapy) were used to induce ovulation in 9 patients with polycystic ovary syndrome (PCO). Ovulation was observed in all twelve treatment cycles in the combined therapy, and two cases (delivery at term, and abortion) of pregnancy were confirmed. In the hMG therapy, ovulation occurred in 22 cycles of 26 treatment cycles. Ovarian hyperstimulation occurred in one cycle in the combined therapy and in 5 cycles (3 ovulated patients) in the 26 hMG therapy. The total dose per cycle of hMG required to induce ovulation in the combined therapy (1,700 +/- 203IU) was significantly lower than in the hMG therapy (2,344 +/- 223IU). In response to Buserelin administration, LH and FSH increased transiently and then declined to the normal range observed in the early follicular phase. The reduced LH level was sustained throughout the hMG administration. The concentration of FSH increased in response to hMG administration, resulting in a change in the LH/FSH ratio. The LH/FSH ratio in the combined therapy was significantly lower than in the hMG therapy. The present data demonstrated that pulsatile subcutaneous administration of hMG associated with Buserelin was effective in inducing ovulation in patients with PCO with a low incidence of serious side effects.

Administration, Intranasal↗
PubMed1988

[Ovarian response and induction of ovulation with human menopausal gonadotropin of different ratio of FSH to LH content in women with ovarian insufficiency].

Human menopausal gonadotropin (hMG) with different ratios of FSH to LH content (FSH: LH = 1.2:1 (GNR 1.2), FSH:LH = 1.6:1 (GNR 1.6), FSH:LH = 3:1 (GNR 3) in biological activity, respectively) was used in this study to examine the effects of these hMGs on ovary, and subsequent follicular maturation and ovulation. In 5 women, 300 IU of hMG (GNR 1.2, GNR 1.6 and GNR 3) was injected in turns during different midfollicular phases of the cycle (day 5-day 9) and serum estradiol (E2) was measured at 0, 24 hrs, 48 hrs, 72 hrs after injection to assess ovarian response to different hMG. Serum E2 response at 24 hrs, 48 hrs, 72 hrs after injection of hMG compared to the preinjected E2 level were 2.2, 1.8, and 1.5 fold with GNR 1.2; 2.6, 2.4 and 1.9 fold with GNR 1.6; and 2.2, 2.4 and 2.3 fold with GNR 3, respectively. These hMGs were administered in turns to women who were suffering from amenorrhea (6 cases), anovulatory (8 cases) and luteal phase dysfunction (10 cases) for treatment of ovarian dysfunction. The mean doses of hMG per cycle required to induce ovulation were 1,125 IU with GNR 1.2, 1,050 IU with GNR 1.6 and 925 IU with GNR 3 in these 24 women. The success rates for ovulation with GNR 1.2, GNR 1.6 and GNR 3 were 70.8, 79.2 and 87.5%. The appearance rates for ovarian hyperstimulation syndrome (OHSS) with GNR 1.2, GNR 1.6, and GNR 3 were 4.2, 8.3 and 8.3%, respectively. These results infer that a different ratio of FSH to LH in hMG has an effect on follicular maturation and ovulation, and that the increase in the rate of ovulation and prevention of OHSS may accompany the regulating of this ratio, and that hMG with a higher FSH content (ratio of FSH to LH is more than three) should be studied further as a promising agent to use in inducing ovulation in women.

Estradiol↗
PubMed1988

Pulsatile GnRH therapy for the induction of ovulation in hypogonadotropic hypogonadism.

Twenty-eight patients with hypogonadotropic hypogonadism resistant to clomiphene therapy were treated with pulsatile GnRH. All the patients ovulated and there were 20 pregnancies in 16 women. Administration of the GnRH sc was successful at inducing ovulation in 19 of 22 patients whereas the treatment was successful in all of the 17 patients treated iv. There was no difference between iv and sc therapy in the rate of ovulation. Treatment was stopped after ovulation and hCG given for luteal support. The follicular phase pulse frequency was usually 90 min. In one patient ovulation only occurred with frequencies of 60 min. Higher pulse doses were usually required with sc therapy for primary amenorrhoeic patients and for those with pituitary lesions. The additional use of clomiphene increased pituitary sensitivity to GnRH resulting in ovulatory cycles in patients refractory to treatment and in ovarian hyperstimulation in a normally responsive patient. Two of the 20 pregnancies were twin--the rest were singletons. None aborted. The median time to conception was 3 ovulatory cycles. Although there were no serious complications with iv or sc therapy, the iv route is now reserved for those patients unresponsive to sc treatment as the sc route is potentially safer and more acceptable to the patient. In correctly selected patients pulsatile GnRH is a highly effective and safe new treatment for the induction of ovulation.

Adult↗
PubMed1988

Ovulation in the merino ewe in the breeding and anoestrous seasons.

The pattern of ovulation of Merino ewes was studied by repeated laparoscopy each 14 days in the anoestrous (n = 97) and breeding (n = 87) seasons. In the anoestrous season the proportion of ewes ovulating did not decrease below 11%, 42% of ewes never ovulated and the remainder fluctuated between the two states. On 20 occasions a clear anovulatory period was interrupted by an isolated spontaneous ovulation. In the breeding season the overall mean proportion of ewes with corpora lutea or albicantia at laparoscopy was 87%, 54% of ewes ovulated regularly throughout while in another 31% absence of corpora lutea or albicantia coincided with the follicular phase of an oestrous cycle as evidenced by an appropriately aged corpora lutea at the next laparoscopy. Of the remaining 15% of the flock 3% had anovulatory periods greater than 14 days while the remainder experienced irregular ovulatory cycles--the majority due to short periods of anovulation but some ewes retained corpora lutea for longer than 14 days while others ovulated twice between successive laparoscopies.

Anestrus↗
PubMed1987

Infusion of gonadotrophin-releasing hormone (GnRH) induces ovulation and fertile oestrus in mares during seasonal anoestrus.

In Exp. 1, 30 Standardbred mares in deep seasonal anoestrus were divided into 3 equal groups and treated with 0, 50 (G50) or 100 (G100) ng GnRH kg-1h-1 for 28 days via osmotic minipumps. Ovulation occurred in 0/10, 3/10 and 7/10 mares respectively (P less than 0.05). Plasma GnRH profiles (Days -6, 0, 2, 6, 12, 20, 28 and 34 relative to pump insertion) were dose-dependent (P less than 0.01) and peaked on Day 12 of infusion. Mean daily plasma LH concentrations were biphasic in treated mares that ovulated, with LH peaks occurring around Day 6 and Days 16-20. By contrast, in treated mares that did not ovulate the initial LH rise was followed by a steady decline to the end of the experiment. LH pulse frequency in treated mares increased between Day 0 and Day 21 of the experiment. LH pulse frequency in G100 mares was higher (P less than 0.05) than in G50 and control mares on Day 3, and higher than the controls on Days 7 and 21 of the experiment. There were no significant differences in LH pulse amplitude between the groups on the days studied. In Exp. 2, 27 Standardbred mares in shallow seasonal anoestrus received no treatment (N = 13) or a subcutaneous infusion of GnRH (100 ng kg-1h-1) via osmotic minipump for 28 days (N = 14). Mares were served by a stallion during oestrus. Day of ovulation was earlier in treated than in control mares (18.6 +/- 2 vs 41.9 +/- 6 days; P less than 0.001). Likewise, time of conception was earlier in treated than in control mares (25.2 +/- 6 vs 49.1 +/- 9 days; P less than 0.05). One mare in the control group failed to conceive while one treated mare conceived to an undetected ovulation. The results show that constant GnRH infusion induces ovulation and fertile oestrus in mares during deep and shallow seasonal anoestrus.

Anestrus↗
PubMed1987

Inhibition of ovulation in the mare by active immunization against LHRH.

To investigate the hypothesis that the onset of the breeding season in the mare may be due to a daylength-induced seasonal increase in LHRH pulse frequency, 5 mares were immunized against LHRH. Beginning 1 December, 5 immunized and 5 untreated control mares were exposed to an abrupt, artificial increase in daylength (16L:8D) to advance the onset of the breeding season. In control mares ovulation occurred 49.6 +/- 3.5 (s.e.m.) days later (18 January), whereas in 3/5 immunized mares ovulation had not occurred by 1 April. In the remaining 2 mares, although ovulation occurred once (Mare 79) or twice (Mare 72) during February, a booster immunization restored acyclicity for the duration of the study (No. 72) or to 30 March (No. 79). The absence or occurrence of ovulation in LHRH-immunized mares appeared to be related to antibody titre, such that the highest antibody titres were observed in those mares that remained anovulatory throughout the experimental period, while low titres were seen in the 2 mares that ovulated. In 3 acyclic immunized mares, LH pulses were not observed in blood samples collected frequently at 2-week intervals from November to January. In contrast, LH pulse frequency in control mares, and in the 2 immunized mares that ovulated, increased from 0/12 h (November) to 2-5/12 h (January). These results confirm our previous observation that, in the mare, the onset of the breeding season is associated with an increase in LH pulse frequency. Furthermore, the results suggest that the increase in LH pulse frequency reflects an increase in pulsatile LHRH release from the hypothalamus.

Animals↗
PubMed1987

Induction of ovulation in cyclic mares by administration of a synthetic prostaglandin, fenprostalene, during oestrus.

Fenprostalene (250 micrograms) or saline was given at 60 h after the onset of oestrus in alternate oestrous periods to 8 mares for 4 cycles. Onset of oestrus and stage of cycle were determined by daily teasing, palpation and ultrasonography until time of treatment when follicular development was monitored at 12-h intervals to confirm ovulation. Serum progesterone concentrations were monitored daily. The interval from treatment to ovulation was significantly decreased (41.25 vs 73.50 h; P = 0.001) as was the duration of oestrus (5.63 vs 6.88 days; P = 0.005). There was no significant difference in the duration of dioestrus (15.88 vs 15.75 days; P = 0.94). There were no significant differences between serum progesterone concentrations at onset of oestrus, at treatment or at examination before ovulation. Follicular size was not significantly different at onset of oestrus or before ovulation. There was no statistically significant difference in follicle size at the time of treatment when a possible horse effect was controlled for, although a significant difference (P less than 0.05) was seen when the horse effect was not taken into account. Clinically, 81% of treated mares had ovulated by 48 h after treatment compared to 31% of the control mares (chi 2; P less than 0.025). The results demonstrate that fenprostalene can effectively hasten time of ovulation in cyclic mares.

Animals↗
PubMedDate not supplied

Prostaglandin E and F concentration in the fimbria of the rabbit fallopian tube increases at the time of ovulation.

To see if the fimbrial concentrations of Prostaglandin E (PGE) and Prostaglandin F (PGF) change in the process of ovulation, these prostaglandins were measured in the fimbriae of one group of 18 doe rabbits using the specific radioimmunoassay; 13 rabbits were bred so as to induce ovulation and 5 rabbits were not bred. The PGE and PGF in the fimbriae of the 13 bred rabbits were 105.4 +/- 18.5 pg/mg of protein and 186 +/- 26.9 pg/mg protein, respectively. In the 5 control unbred animals, the fimbrial PGE and PGF concentrations were 39.6 +/- 5.9 pg/mg protein and 111 +/- 14.7 pg/mg protein, respectively (p less than 0.05). In an additional group of 8 rabbits (2 before ovulation and 6 after ovulation), it was found that the rise in the PGE and PGF concentration association with ovulation was maximal in fimbriae harvested immediately before ovulation (8 hours-8 hours 30 postcoitally) (p less than 0.001). These findings are consistent with the hypothesis that fimbrial PGE and PGF play a role in the process of ovum retrieval in the rabbit.

Animals↗
PubMed1985

[Induction of ovulation in 1985].

There are many methods that can be used to induce ovulation when there is a fault in ovulation in patients who have normal prolactin levels. These are: Bringing the weight to a normal level. Giving Clomiphene. Giving Tamoxifen. Giving cyclofenil and bromocriptine, which really have no more effect than giving a placebo. Giving gonadotrophins in a classical way. This is very useful where there is hypogonadic amenorrhoea but much less useful when the failure of ovulation occurs with normal gonadic function. It is accompanied by a risk of multiple pregnancies and of hyperstimulation, which should be monitored by ultrasound very strictly so that it cannot become too serious. The use of purified FSH which theoretically should be more adequate, at least in cases where the gonadic function is normal in spite of failure of ovulation. Pulsatile administration of LHRH, which in cases of hypothalamic amenorrhoea carries less total risk than giving gonadotrophins. Finally, wedge resection of the ovaries which is reversed for polycystic ovaries that are larger than normal in size, and allied methods. The first choice for hypogonadic hypothalamic amenorrhoea would seem to be the LHRH pump; and for failure of ovulation with normal gonadic function Clomiphene or Tamoxifen. When anti-oestrogens fail to correct these latter cases one can choose according to the case between gonadotrophins, choosing if possible pure FSH, and/or wedge resection. In the last resort in these cases the LHRH pump can be used. The frequent failure of these methods show that perhaps it is possible to create a hypogonadotrophic hypogonadism by giving agonists for a long time or antagonists to LHRH in such a way that a second attempt can be made to induce ovulation using gonadotrophins in better conditions of efficacy and safety.

Amenorrhea↗
PubMed1980

[Hemodynamical and histological studies on ovarian blood flow during ovulation (author's transl)].

The author, in an attempt to investigate the mechanism of ovulation, conducted studies on ovarian blood flow hemodynamically and ovarian vessels histologically during ovulation induced by FSH and LH in rabbits. Continuous measurement of ovarian blood flow was facilitated by the crossed-thermocouple inserted into the unilateral ovary relatively close to its cortex. Histological changes of the ovarian blood vessels were observed every two hours and 13 h after LH administration. (1) The ovarian blood flow showed a rapid increase as 116.6 +/- 4.3% (M +/- S.E) at 15 min, 122.1 +/- 5.1% at 30 min following LH administration and maintained its high level percentage during the subsequent 2 h to 4 h, showing the peak with 156.2 +/- 9.1%. The ovarian blood flow showed a gradual decrease after 4 h. (2) A dilatation was observed in the perifollicular and stromal vessels from 2 h. The vessels maintained a considerable dilatation during 4 h to 8 h and the most conspicuous vasodilatation was manifested, especially at the apical vessels, at 10 to 13 h just prior to ovulation. Although the wall of the apical vessels was remarkably thin at that time, the overswelled apical vessels remained until ovulation. The ovulation was not seen without the rupture of the apical perifollicular vessels. These hemodynamic and histological results suggest a congestion in ovarian blood vessels during the ovulatory period. Such blood congestion presumably plays a significant role in the mechanism leading to ovulation.

Animals↗
PubMed1982

[Establishment of puberty in the doe rabbit (folliculogenesis and ovulation. Effect of rationing the diet].

We used 307 Californian doe-rabbits divided into 7 experimental groups. The first 4 groups, fed an ad libitum diet, were presented to the male at 11, 14, 17 or 20 weeks of age. The other 3 groups were fed a 75 p. 100 ad libitum diet and were presented to the male at 14, 17 and 20 weeks of age. Three to 5 does per group were killed at 8 postcoitum hours to check the ovarian follicles, and the remaining females, after effective mating, were killed 12 days later to check the ovulation rate. Acceptation of mating was homogeneous (75-80 p. 100) in all the groups, except in the one with the restricted diet presented to the male at 14 weeks of age (55 p. 100). In ad libitum-fed does, the percentage of females mated and ovulating reached one-third at 14 weeks and two-thirds at 17 and 20 weeks. Rationing retarded by 3 weeks live-weight gain and ability to ovulate. Whatever the diet given, the mean weight of does of this breed had to reach 3 kg before the first ovulation occurred and 3.3 kg before the percentage of females ovulating after mating became normal. The number of ova found in ovulating females did not differ statistically in any of the groups, but the rationed does tended to have fewer ova (- 8 p. 100) in direct relation to their live weight. In fact, whatever the diet, the number of ova increased more than 2-units for a weight increase of 1 kg of live weight. In ad-libitum-fed does, the follicle population doubled between 11 and 14 weeks, then decreased to attain at 20 weeks the value found at 11 weeks. Although this population was unimodal at 11 weeks, it became bimodal afterwards and was clearly so at 17-20 weeks. The second mode represented 5 then 8 p. 100 of the total follicles which were large-size (greater than 407000 mu2) and corresponded to preovulatory follicles. The number of atretic follicles followed a similar pattern. Rationing did not change the follicular population of the first mode; on the contrary, it altered the size and number of the large-sized follicle population of the second mode. Rationing also increased the percentage of atretic preovulatory follicles in the two oldest groups.

Aging↗
PubMed1980

Blockade of ovulation by methadone in the rat: a central nervous system-mediated acute effect.

Morphine blocks ovulation in the rat and is associated with irregular menstrual cycles in humans. Methadone, the synthetic narcotic used to treat heroin addiction, was tested in rats for its ability to block ovulation. Equal doses of methadone were administered subcutaneously at 13:00, 14:00 and 15:00 hr on proestrus. Three different total (cumulative) doses were tested: 6, 9 and 15 mg/kg, in Wistar and Sprague-Dawley rats. The 6 mg/kg dose was ineffective, 9 mg/kg affected by Sprague-Dawley, whereas the 15 mg/kg dose blocked ovulation in both strains. Injection of saline at 13:00, 14:00 and 15:00 hr, or of the narcotic antagonist naltrexone at 12:00 had no effect on ovulation. Naltrexone prevented the blockade of ovulation by methadone, implicating narcotic receptors in the mediation of this action of methadone. Electrochemical stimulation of the medial preoptic area of the brain, or administration of exogenous luteinizing hormone overcame methadone's blockade of ovulation suggesting that the drug is acting via the central nervous system. The results of these studies suggest that menstrual dysfunction may not be a major problem in the clinical application of methadone.

Animals↗
PubMed1995

Immunological manipulation of ovulation rate for twinning in cattle.

Unlike in sheep, in which immunization against androstenedione causes mild and reasonably controlled increased ovulation rate, in similar studies cattle showed highly variable responses ranging from increased ovulation rate and fertility through to anovulation/anoestrous or superovulation. As a consequence, interest in manipulation of ovulation rate through this approach has declined and is now focused on immunological manipulation of endogenous inhibin following successful studies in sheep. Studies have concentrated on developing a prototype inhibin-based vaccine to be used for twinning in the Australian beef industry. The prototype vaccine (with recombinant ovine inhibin-alpha.3 fusion protein and Montanide:Marcol adjuvant) has proved to be very potent and control of the degree of ovarian stimulation has not been possible. The proportion of cattle with increased ovulation rate after inhibin immunization is affected by timing of booster vaccination within the ovarian cycle, time after vaccination, vaccine formulation and possibly genotype. Physiological studies show that cattle responding to the inhibin vaccine have increased plasma inhibin binding of native bovine inhibin, high plasma FSH concentrations, greater numbers of large (> or = 8 mm) follicles and fewer small (< 5 mm) follicles during the preovulatory wave of follicular development compared with control or non-responding animals. Significant correlations among the response parameters (i.e. inhibin binding, plasma FSH concentrations, number of large follicles and ovulation rate) have been demonstrated. The results indicate that greater understanding of the various processes of folliculogenesis will be necessary to achieve a controlled increase in ovulation rate in cattle.

Animals↗
PubMedDate not supplied

[Therapeutic induction of ovulation: towards the replacement of hCG with LH].

Ovulation has exclusively been triggered with Human Chorionic Gonadotropin (hCG) since the earlier times of follicular stimulation with Pregnant Mare Serum Gonadotropins (PMSG). hCG was chosen in regard of its LH-like effect, when isolated or purified human LH was not available. hCG, however, is not the physiologic hormone for ovulation triggering and shows many discrepancies in pharmacokinetics and bio-availability with LH, accounting for the permanent risk for ovarian hyperstimulation syndrome (OHSS) following hCG administration. Human recombinant LH should become available in the coming years, but it is at present possible to trigger ovulation in hMG--stimulated patients with their own pituitary LH, using a short-acting GnRH agonist. Literature shows that this method of triggering ovulation in in vitro fertilization (IVF) cycles as well as in non IVF cycles results in a satisfactory ovulatory process and pregnancy rates comparable to those observed following hCG administration. More over, triggering ovulation with endogenous LH considerably reduces the risks for OHSS, and perhaps for multiple pregnancies. Optimum posology for each GnRH agonist available remains to be evaluated to minimize the occurrence of short luteal phases following ovulation triggering with endogenous LH.

Biological Availability↗
PubMed1996

Variances of additive and dominance genetic effects for ovulation and twinning rates in a population selected for twinning.

Estimates of variances due to additive and dominance genetic effects and permanent and temporary environmental effects were obtained for ovulation and twinning rates from a composite population selected for twinning rate. Measures of ovulation rate after 11 mo of age on 2,317 heifers with a total of 19,209 measures were used. Twinning measures were on 1,522 first-parity cows, 1,311 later-parity cows with a total of 3,571 measures, and 1,704 all-parity cows with 5,100 measures. Models included fixed effects of year-season-age at calving for twinning, and year-season of birth, age in months, and calendar month of measurement for ovulation rate. Four analyses were performed for each sample: combinations of models with and without dominance effects and with and without covariates for fractions of inheritance from the seven foundation groups. Variance components as fractions of phenotypic variance for analysis of all ovulation rate measures were .076, .000, and .045 for additive, dominance, and permanent environmental effects with no foundation groups in the model and .069, .000, and .050 with foundation groups in the model. For sums of eight measures, the estimates were .287 and .000 for relative variances of additive and dominance effects with groups in the model and .316 and .000 with groups ignored. For twinning rate for first parity, estimates were .126 and .209 for relative variances of additive and dominance effects; for later parities, estimates were .045 and .035 for models including foundation group effects. The results suggest lack of dominance effects in expression of ovulation rate and the possibility of dominance effects for embryo and(or) fetal survival or conception rate because twinning rate is a function of ovulation, conception, and embryo and(or) fetal survival rates.

Aging↗
PubMed1998

Impaired ovulation in mice with targeted deletion of the neuronal isoform of nitric oxide synthase.

BACKGROUND: Nitric oxide (NO) plays an important role in numerous reproductive processes. To date, most studies have assessed the role of NO by using nonspecific pharmacological inhibitors of the precursor to NO, nitric oxide synthase (NOS). These pharmacological NOS inhibitors suppress all isoforms of NOS; thus, the precise contribution of each isoform to female reproductive physiology is unknown. The purpose of this study was to determine the specific role of neuronal NOS (nNOS) in the regulation of ovulation in female mice lacking the gene that encodes for nNOS (nNOS-/-). MATERIALS AND METHODS: Ovulation was assessed in wild-type (WT) and nNOS-/- female mice by examining the number of ovarian rupture sites and number of oocytes recovered from the oviducts following mating or exposure to exogenous gonadotropins (i.e., 5 IU pregnant mares serum gonadotropin [PMSG] and 5 IU human chorionic gonadotropin [hCG]). Ovulatory efficiency was determined as the number of ovulated oocytes per number of ovarian rupture sites. To examine whether ovulatory deficits in nNOS-/- mice were due to alternations in central mechanisms, plasma luteinizing hormone (LH) concentrations were assessed in WT and nNOS-/- mice that were challenged with 25 ng of gonadotropin-releasing hormone (GnRH). To determine whether ovulatory deficits in nNOS-/- mice were due to local ovulation processes, nerves innervating the reproductive tract of WT and nNOS-/- females were examined for the presence of nNOS protein. RESULTS: There were substantial fertility deficits in nNOS-/- female mice; the nNOS-/- mice had fewer oocytes in their oviducts following spontaneous and gonadotropin-stimulated ovulation. Pituitary responsiveness to exogenous GnRH challenge was intact in nNOS-/- mice. Dense nNOS protein staining was observed in nerves innervating the reproductive tracts of WT mice. CONCLUSIONS: The reproductive deficits in nNOS-/- females are most likely due to alternations in the transfer of oocytes from the ovaries to the oviducts during ovulation. These results suggest that defects in neuronally derived NO production may contribute to female infertility.

Animals↗
PubMed1998

Morphologic comparison of ovulated and in vitro-matured porcine oocytes, with particular reference to polyspermy after in vitro fertilization.

This study was conducted to evaluate morphologic differences in pig oocytes matured in vivo and in vitro, with particular reference to the potential relationship between oocyte morphology and the occurrence of polyspermy after in vitro fertilization (IVF). In vivo-matured oocytes were surgically recovered from the oviducts of gilts with ovulated follicles on day 2 of estrus, and in vitro-matured oocytes were obtained by culturing follicular oocytes in a oocyte maturation system that has resulted previously in production of live offspring following IVF. Comparisons were made of the cytoplasm density, the diameter of oocytes with or without zona pellucida (ZP), the thickness of the ZP, the size of the perivitelline space (PVS), ZP dissolution time, and cortical granule (CG) distribution before IVF, and CG exocytosis and polyspermic penetration after IVF. Oviductal oocytes have clear areas in the cytoplasm cortex, while in vitro-matured oocytes have very dense cortex. The diameter of ovulated oocytes with ZPs was significantly (P < 0.001) greater than that of in vitro-matured oocytes. However, no difference was observed in the diameter of the oocyte proper. Significantly (P < 0.001) thicker ZPs and wider PVSs were observed in the ovulated oocytes. The ZPs of ovulated oocytes were not dissolved by exposure to 0.1% pronase within 2 hr, but the ZPs of in vitro-matured oocytes were dissolved within 131.7 +/- 7.6 sec. The ZPs of ovulated oocytes, but not of in vitro-matured oocytes, were strongly labeled by a lectin from archis hypogaea that is specific for beta-D-Gal(1-3)-D-GalNAc. Polyspermy rate was significantly (P < 0.01) higher for in vitro-matured oocytes (65%) than for ovulated oocytes (28%). CGs of oviductal oocytes appeared more aggregated than those of in vitro-matured oocytes. Most of CGs were released from both groups of oocytes 6 hr after IVF regardless of whether they were polyspermic or monospermic oocytes. These results indicate that in vitro-matured and in vivo-matured pig oocytes possess equal ability to release CGs on sperm penetration. Unknown changes in the extracellular matrix and/or cytoplasm of the oocytes while in the oviduct may play an important role(s) in the establishment of a functional black to polyspermy in pig oocytes.

Animals↗