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PubMed1995

The petunia MADS box gene FBP11 determines ovule identity.

In contrast to the wealth of information relating to genes regulating floral meristem and floral organ identity, only limited data are available concerning genes that are involved in determining and regulating the identity and development of an ovule. We have recently isolated the floral binding protein 11 (FBP11) MADS box gene from petunia and found that it is expressed exclusively in ovule primordia and subsequently in the ovules, suggesting a role for this gene in ovule formation. To test this hypothesis, we constructed a recombinant gene in which the full-size FBP11 cDNA was placed under the control of a strong cauliflower mosaic virus 35S promoter. Transgenic petunia plants expressing this chimeric gene have ovulelike structures on the adaxial side of the sepals and the abaxial side of the petals. Detailed morphological studies showed that these ovulelike structures are true ovules. RNA gel blot analysis was performed to investigate ectopic FBP11 expression in relation to the expression of the closely related FBP7 gene and the putative petunia class C-type homeotic genes FBP6 and pMADS3. Our results indicate that FBP11 represents an ovule identity gene. A new model describing the mode of action of FBP11 as an additional class D MADS box gene is presented.

Base Sequence↗
PubMed1999

Systemic absorption of clindamycin after intravaginal administration of clindamycin phosphate ovule or cream.

The absolute bioavailability of clindamycin phosphate vaginal ovule with comparison to a reference treatment of clindamycin phosphate sterile solution, as well as the relative bioavailability of the ovule compared to clindamycin phosphate vaginal cream, was evaluated in 12 healthy adult female volunteers. Subjects were randomly assigned to receive either the ovule or cream formulation intravaginally for 3 consecutive days during the two-way crossover portion of the study. During a third treatment period, all subjects received 100 mg of clindamycin as a 4-minute intravenous infusion of clindamycin phosphate sterile solution (10 mg/mL). Clindamycin concentrations in serum were assayed by a high-performance liquid chromatography method with detection by mass spectrometry. Pharmacokinetic analyses of the serum data indicated low systemic absorption of clindamycin from the vaginal cream (about 4%), consistent with results of previous bioavailability studies. Following intravaginal administration of the clindamycin phosphate ovule, systemic absorption averaged 30%, which was approximately sevenfold greater than after dosing with the vaginal cream. The higher drug absorption for the ovule may be related to differences in formulation effects on the vaginal membrane. Nevertheless, systemic exposure to clindamycin from the ovule is still considerably lower than from a therapeutic oral dose.

Absorption↗
PubMed2006

Distinct short-range ovule signals attract or repel Arabidopsis thaliana pollen tubes in vitro.

BACKGROUND: Pollen tubes deliver sperm after navigating through flower tissues in response to attractive and repulsive cues. Genetic analyses in maize and Arabidopsis thaliana and cell ablation studies in Torenia fournieri have shown that the female gametophyte (the 7-celled haploid embryo sac within an ovule) and surrounding diploid tissues are essential for guiding pollen tubes to ovules. The variety and inaccessibility of these cells and tissues has made it challenging to characterize the sources of guidance signals and the dynamic responses they elicit in the pollen tubes. RESULTS: Here we developed an in vitro assay to study pollen tube guidance to excised A. thaliana ovules. Using this assay we discerned the temporal and spatial regulation and species-specificity of late stage guidance signals and characterized the dynamics of pollen tube responses. We established that unfertilized A. thaliana ovules emit diffusible, developmentally regulated, species-specific attractants, and demonstrated that ovules penetrated by pollen tubes rapidly release diffusible pollen tube repellents. CONCLUSION: These results demonstrate that in vitro pollen tube guidance to excised A. thaliana ovules efficiently recapitulates much of in vivo pollen tube behaviour during the final stages of pollen tube growth. This assay will aid in confirming the roles of candidate guidance molecules, exploring the phenotypes of A. thaliana pollen tube guidance mutants and characterizing interspecies pollination interactions.

Arabidopsis↗
PubMed1997

Dissection of sexual organ ontogenesis: a genetic analysis of ovule development in Arabidopsis thaliana.

Understanding organogenesis remains a major challenge in biology. Specification, initiation, pattern formation and cellular morphogenesis, have to be integrated to generate the final three-dimensional architecture of a multicellular organ. To tackle this problem we have chosen the ovules of the flowering plant Arabidopsis thaliana as a model system. In a first step towards a functional analysis of ovule development, we performed a large-scale genetic screen and isolated a number of sterile mutants with aberrant ovule development, We provide indirect genetic evidence for the existence of proximal-distal pattern formation in the Arabidopsis ovule primordium. The analysis of the mutants has identified genes that act at an intermediate regulatory level and control initiation of morphogenesis in response to proximal-distal patterning. A second group of genes functions at a subordinate control level and regulates general cellular processes of morphogenesis. A large group of male and female sterile mutants shows defects restricted to early or late gametogenesis. In addition, we propose that the mature ovule obtains its overall curved shape by at least three different processes that act in only one domain of the ovule.

Arabidopsis↗
PubMed1991

Relationship between blood radioimmunoreactive beta-endorphin and hand skin temperature during the electro-acupuncture induction of ovulation.

Thirteen cycles of anovulation menstruation in 11 cases were treated with Electro-Acupuncture (EA) ovulation induction. In 6 of these cycles which showed ovulation, the hand skin temperature (HST) of these patients was increased after EA treatment. In the other 7 cycles ovulation was not induced. There were no regular changes in HST of 5 normal subjects. The level of radioimmunoreactive beta-endorphin (r beta-E) fluctuated, and returned to the preacupunctural level in 30 min. after withdrawal of needles in normal subjects. After EA, the level of blood r beta-E in cycles with ovulation declined or maintained the range of normal subjects. But the level of blood r beta-E in cycles in which the induction failed to cause ovulation was kept higher that that of normal. (P less than 0.05). There was a negative correlation in the decrease of blood r beta-E and increase of HST after EA (r = 0.677, P less than 0.01). EA is able to regulate the function of the hypothalamic-pituitary-ovarian axis. Since a good response is usually accompanied with the increase of HST, monitoring HST may provide a rough but simple method for predicting the curative effect of EA. The role of r beta-E in the mechanism of EA ovulation induction was discussed.

Anovulation↗
PubMed1987

Response to repetitive cycles of ovulation induction in the same women.

It has been theorized that the administration of human menopausal gonadotropin (hMG) in consecutive menstrual cycles will result in a poor follicular response in the second cycle. To examine this, 50 women undergoing ovulation induction in two consecutive cycles were assessed, using in each the same induction regimen during the initial 5 days. The remainder of each cycle was individualized according to their response. Nine women were anovulatory, 19 were oligoovulatory, and 22 ovulated regularly in unstimulated cycles. In repeat cycles only 3 of 50 had poor follicular development and did not receive human chorionic gonadotropin (hCG); all were anovulatory. Forty-two of 50 of the first cycles had continually rising estradiol (E2), while 43 of 47 of the second cycles had rising E2 patterns. Grouping the peak E2 prior to hCG in the ranges less than 300, 300-699, 700-1099, and greater than or equal to 1100 pg/ml, peaks in the second cycle were similar in 25 of 50, lower in 16, and higher in 9. Only 3 of 9 anovulatory women had similar peaks, as compared to 22 of 41 of the oligoovulatory and regularly ovulating women. Comparing the second to the first cycle, the day of hCG was within 1 day in 28 of 50 women, 2 or more days less than the first cycle in 6, and 2 or more days greater than the first cycle in 11. We conclude that in a successive cycle of ovulation induction (i) the follicular response is impaired in anovulatory women, but (ii) in oligoovulatory or regularly ovulating women, clinically significant differences in the estradiol response do not occur.

Chorionic Gonadotropin↗
PubMed1994

Effects of anti-progesterone compound RU486 on ovulation in immature mice treated with PMSG/hCG.

The effects of RU486, a competitive antagonist of progesterone, on ovulation were studied in PMSG/hCG-treated immature mice. PMSG/hCG was administered to 3-week-old female mice to induce ovulation. A dose of 0.5 mg of RU486 was administered 3 h before hCG injection, simultaneously with hCG injection, or 3, 4.5, 6, 7.5 or 9 h after hCG administration. The lowest number of ovulated eggs was observed in the group given RU486 6 h after hCG injection. Although the mean number of ovulated eggs was only 4.4 in this group, it was increased to 25.7 by supplementary administration of 2.0 mg of progesterone. It was demonstrated that RU486 had inhibitory effects on ovulation, and the inhibition could be prevented by supplementary administration of progesterone.

Animals↗
PubMed1988

Gonadotropin-induced ovulation in a reptile (Anolis carolinensis): histological observations.

Although much is known about morphological changes in the apex of the mammalian ovarian follicle prior to its rupture (ovulation), information about this process in nonmammalian vertebrates is limited to only a few species. We describe here the histological changes in the stigma of the lizard (Anolis carolinensis) ovarian follicle preceding FSH-induced ovulation. Females with a large vitellogenic follicle received two injections, separated by 7 hr, of either porcine FSH (25 micrograms) or saline, and then were sampled at 6, 9, 12, 15, 18, and 24 hr after the first injection. Thus, all but the 6-hr group received two injections. By 12 hr, about half of the FSH-treated females had ovulated, and most had ovulated by 15 hr. In contrast, only 1 of 40 control females ovulated. Large unovulated follicles were fixed and bisected through the circular stigma; one hemisphere was embedded in paraffin and stained with Mallory's trichrome, and the other was embedded in plastic and stained with toluidine blue. FSH treatment produced marked histological changes in the stigma region, as well as alterations in nonstigmal areas of the follicle. The membrana granulosa of control follicles consisted of a single layer of squamous, darkly staining granulosa cells. After FSH treatment, nonstigmal granulosa cells separated slightly, and their nuclei became more clear and assumed an oval shape; in the stigma, these cells became widely separated, with round, light-staining nuclei containing one or two prominent nucleoli. The nonstigmal theca of FSH-treated follicles was similar to that of control follicles except that collagen fibers were more dissociated. In the stigma, collagen fibers were widely dissociated, and the theca swelled, presumably due to accumulation of extracellular fluid. Abundant fluid accumulated in the stigma, especially between the granulosa cells and their basement membrane and between the tunica albuginea and the theca externa. These changes in the lizard stigma are similar to those reported in mammals except that no marked inflammatory response occurs in the lizard stigma. We hypothesize that the Anolis follicle undergoes preovulatory luteinization, and that the stigma exhibits ischemic necrosis before rupture.

Animals↗
PubMed2005

Safety and efficacy of low dose hCG for luteal support after triggering ovulation with a GnRH agonist in cases of polyfollicular development.

OBJECTIVE: The use of GnRH agonists instead of hCG to trigger ovulation seems to be an effective way to prevent subsequent hCG induced ovarian hyperstimulation in cases of polyfollicular development. But conflicting results are reported on the efficiency of subsequent luteal support using hCG and/or progesterone supplementation. STUDY DESIGN: We investigated the efficiency and safety of different luteal support regimes in low dose gonadotropin stimulation non-ivf cycles. A risk for an imminent ovarian hyperstimulation was assumed if preovulatory estradiol levels rose up higher than 700 pg/ml and more than 12 intermediate sized follicles (8-14 mm) were observed. Thirty-six women received 0.5mg Triptorelin subcutaneously to trigger the ovulation inducing LH surge. After randomization, luteal support regimes started on day 2 after the Triptorelin administration with injections every second day five times in all. Group (a) received 5 x 1000 IU hCG, group (b) received 5 x 500 IU hCG, and group (c) received 5 x 250 mg progesterone, intramuscularly. The monitoring of the ovulation period and the subsequent luteal phase included sonographic measurement of ovarian diameter and estimation of LH, FSH, estradiol and progesterone levels 10 and 34 h as well as 8 days after Triptorelin administration. RESULTS: We could prove ovulation in all women and did not find symptoms of ovarian hyperstimulation in any case. Midluteal controls showed extremely low gonadotropins in all groups indicating a long lasting pituitary down regulation after one injection of 0.5 mg Triptorelin. We found high normal sex steroid levels in both hCG groups. The progesterone group displayed a marked luteal phase defect with low levels of progesterone and estradiol in all cases. CONCLUSION: The use of GnRH agonist in cases of polyfollicular development is capable to induce ovulation without a subsequent ovarian enlargement and/or any sign of hyperstimulation syndrome. Luteal support by low dose hCG does not counteract the benefit of GnRH agonist in preventing an ovarian hyperstimulation syndrome, but seems to remedy at least in part the possible deleterious effects of GnRH agonists on luteal functionality.

Adult↗
PubMed1998

A regimen of oral contraceptives restricted to the periovulatory period may permit folliculogenesis but inhibit ovulation.

Increased safety of oral contraceptives (OC) has resulted from a reduction in the estrogen and progestin content per tablet. A reduction in the number of hormonally active pills and their placement at critical points within the cycle may provide a novel regimen for further reducing the hormonal content of OC per cycle and their attendant side effects without compromising efficacy. The objective of this study was to determine the effectiveness of two OC regimens that incorporate a delayed start and limited midcycle use of the combination of ethinyl estradiol and norethindrone, and limited use of norethindrone only during the second half of the cycle. Main outcome measures were defined as ovulation, serum concentrations of estradiol (E2), luteinizing hormone (LH), follicle stimulating hormone (FSH), progesterone (P), follicular diameters, and endometrial thickness. Volunteers were issued blister packs containing 28 pills and randomized to one of two groups. Group 1 used a combination of 50 micrograms ethinyl estradiol and 1 mg norethindrone per tablet day 6-10, and 0.70 mg norethindrone only day 11-19. Placebo tablets were used on days 1-5 and day 20-28. Group 2 used a combination of 50 micrograms ethinyl estradiol and 1 mg norethindrone per tablet on day 8-12, and 0.70 mg norethindrone only on day 13-21. Placebo tablets were used on day 1-7 and day 22-28. A total of 20 cycles were studied using 10 volunteers. To assess any possible carryover effect, two successive cycles were studied for each subject. Serum sampling for E2, FSH, LH, and P, and transvaginal ultrasound imaging to assess endometrial thickness and follicle diameter were carried out at 4 day intervals throughout the cycle. One ovulation occurred in 10 cycles in group 1. Five ovulations occurred in 10 cycles in group 2. All ovulations, regardless of group, occurred in the second cycle. Peak E2 concentrations were not significantly different between groups (152.04 +/- 107.1 pg/mL vs 162.1 +/- 56.1 pg/mL [mean +/- SD] for groups 1 and 2, respectively] but occurred earlier in the cycle in group 1. No differences were noted between the groups in serum concentrations of FSH or LH for any given cycle day. Maximum follicle diameters were not different between groups 1 and 2, regardless of ovulatory status (20.5 +/- 8.1 mm2 vs 20.6 +/- 14.2 mm2, respectively). Ultrasound imaging assessment of midcycle follicle growth revealed diameters ranging from 18.5 mm2 to 34.0 mm2 with gradual resolution through the second half of the cycle in anovulatory cycles, and 16.0 mm2 to 23.5 mm2 with abrupt disappearance in ovulatory cycles. Endometrial thickness did not exceed 10 mm for any anovulatory cycle regardless of group, but ranged from 6 to 9 and 6 to 11 during the luteal phase of ovulatory cycles of groups 1 and 2, respectively. Peak serum P concentrations at midluteal phase in ovulatory cycles ranged from 9.2 ng/ml to 18.2 ng/ml. Data from this preliminary study suggest that ovulation may be prevented with a combination of ethinyl estradiol and norethindrone started as late as cycle day 6 and limited to 5 days' duration using norethindrone only for 9 days during the second half of the cycle. Such a restricted regimen may offer both an effective method of contraception and a means of further reducing both estrogen and progestin content per cycle and the possible short and long term adverse side effects of these hormones.

Adult↗
PubMed2000

Phenytoin inhibits both the first ovulation and uterine development in gonadotropin-primed immature rats.

This study was planned to determine the effects and possible mechanism of action of phenytoin on development of the reproductive tract and first ovulation in immature rats. Rats were injected s.c. with 5 IU of equine chorionic gonadotrophin (equine CG) on day 26 to induce ovarian and uterine development. Treatment with phenytoin (140 mg/kg) at 1200 h on day 28, which induces serum levels approximately twice those reached with the clinical dose as anticorvulsant drug for humans, was effective for inhibiting the first ovulation and normal secretion of serum follicle - stimulating hormone and luteinizing hormone (LH) on day 29 as well as the preovulatory gonadotrophin surge on day 28. The block of ovulation was overcome by administration of human chorionic gonadotrophin or LH-releasing hormone on day 28. Simultaneous treatment with equine CG and phenytoin at 0800 h on day 26 did not affect either ovarian weight or ovarian hormones secretion, whereas phenytoin clearly inhibited the normal increase in uterine weight on day 27. Furthermore, phenytoin suppressed uterine growth after 17beta-oestradiol injection. These results indicate that phenytoin inhibits the first ovulation by inhibiting the gonadotrophin surge and further, that the drug impairs the stimulatory effects of oestrogen on uterine proliferation in the gonadotropin-induced ovulation model.

Animals↗
PubMed1986

Induction of ovulation in the postpartum rhesus monkey: factors determining success in obtaining primate luteal tissue.

Ovulation induction in the postpartum rhesus monkey was attempted with the use of purified human pituitary gonadotropins for assessment of (1) whether this procedure could be used to provide a source of luteal tissue; (2) the extent of ovarian responsiveness to gonadotropic stimulation; (3) factors that might facilitate ovulation induction during the peurperium; and (4) factors that might be a contributory cause of induction failure. Twenty rhesus monkeys were treated with purified human follicle-stimulating hormone (hFSH) and human luteinizing hormone (hLH) twice daily, beginning on days 0, 10, or 20 postpartum, with or without prior administration of bromocriptine. Laparotomies were performed during the midluteal phase. Ovaries were examined, and all corpora lutea were removed. Neither the day of beginning the gonadotropin treatment nor bromocriptine administration had a significant effect on the success rate of ovulation induction, which averaged 60% overall. Inductions begun during July had a significantly (P less than 0.025) lower success rate than those started at other times of the year. Antibodies to hFSH and hLH were detected in serum from monkeys that had undergone ovulation induction. Antibodies to hFSH, but not hLH, were associated with significantly reduced induction success (P less than 0.05). Plasma estradiol rose in response to gonadotropin treatment, and the induced follicular phase averaged 13.6 +/- 0.7 days. In all animals judged to have ovulated, corpora lutea were observed at laparotomy, and plasma concentrations of progesterone were significantly elevated (13.8 +/- 3.8 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Prediction of ovulation with the use of oral and vaginal electrical measurements during treatment with clomiphene citrate.

This study was undertaken to evaluate the usefulness of measuring salivary and vaginal electrical resistance in monitoring ovulation induced by clomiphene citrate (CC). Data from 28 cycles of 12 women treated with CC were compared with those of 18 cycles of 13 women who were ovulating spontaneously. Patterns of salivary readings in CC and spontaneous cycles were similar and showed a preovulatory peak 6.2 (mean) days before the luteinizing hormone peak. The trend in vaginal readings for CC cycles differed from that of spontaneous ovulations in that the values were depressed during and shortly after CC therapy. Occurrence of the periovulatory nadir and subsequent rise was common to both groups. The rise in vaginal readings CC cycles occurred within 24 hours of the luteinizing hormone peak in 88% of cases. Retrospective analysis showed that, based on this method, artificial insemination would have been timed appropriately in 25 of 27 cycles or in every cycle, depending on the protocol used. The results indicate that the method is equally useful for predicting and confirming ovulation in cycles in which CC was used to induce ovulation as it is in spontaneous cycles.

Adult↗
PubMed2002

Embryo recovery and pregnancy rates after the delay of ovulation and fixed time insemination in superstimulated beef cows.

The aim of this study was to evaluate the effect of delaying ovulation subsequent to superstimulation of follicular growth in beef cows (Bos indicus) on embryo recovery rates and the capacity of embryos to establish pregnancies. Ovulation was delayed by three treatments using either progesterone (CIDR-B) or a GnRH agonist (deslorelin). Multiparous Nelore cows (n = 24) received three of four superstimulation treatments in an incomplete block design (n = 18 per group). Cows in Groups CTRL, P48 and P60 were treated with a CIDR-B device plus estradiol benzoate (EB, 4 mg, i.m.) on Day-5, while cows in Group D60 were implanted with deslorelin on Day-7. Cows were superstimulated with FSH (Folltropin-V, 200 mg), from Day 0 to 3, using twice daily injections in decreasing amounts. All cows were treated with a luteolytic dose of prostaglandin on Day 2 (08:00 h). CIDR-B devices were removed as follows: Group CTRL, Day 2 (20:00 h); Group P48, Day 4 (08:00 h); Group P60, Day 4 (20:00 h). Cows in Group CTRL were inseminated at 10, 20 and 30 h after first detected estrus. Ovulation was induced for cows in Group P48 (Day 4, 08:00 h) and Groups P60 and D60 (Day 4, 20:00 h) by injection of LH (Lutropin, 25 mg, i.m.), and these cows were inseminated 10 and 20 h after treatment with LH. Embryos were recovered on Days 11 or 12, graded and transferred to synchronized recipients. Pregnancies were determined by ultrasonography around Day 100. Data were analyzed by mixed procedure, Kruskal-Wallis and Chi-square tests. The number of ova/embryos, transferable embryos (mean +/- SEM) and pregnancy rates (%) were as follows, respectively: Group CTRL (10.8+/-1.8, 6.1+/-1.3, 51.5), P48 (12.6+/-1.9, 7.1+/-1.0, 52.3), P60 (10.5+/-1.6, 5.7+/-1.3, 40.0) and D60 (10.3+/-1.7, 5.0+/-1.2, 50.0). There were no significant differences among the groups (P > 0.05). It was concluded that fixed time AI in association with induced ovulation did not influence embryo recovery. Furthermore, pregnancy rates in embryos recovered from cows with delayed ovulation were similar to those in embryos obtained from cows treated with a conventional superstimulation protocol.

Animals↗
PubMed2001

Ultrasonographic study of the effects of the corpus luteum on antral follicular development in unilaterally ovulating western white-faced ewes.

The objective of this study was to examine the local effects of the corpus luteum (CL) on ovarian antral follicle development by looking at follicle populations and dynamics in ovaries with or without CL, in unilaterally ovulating ewes, using a retrospective analysis of daily ultrasonographic records. The present report summarises the data from the first luteal phase of the breeding season (August-October; n = 4), a luteal phase in the mid-breeding season (November-December; n = 5), the last luteal phase of the breeding season (January-March; n = 5), and the luteal phase after GnRH-induced ovulations in mid-anoestrus (May-June; n = 4) of western white-faced ewes. Mean daily numbers of 3mm follicles that did not grow any larger were significantly reduced in the CL-containing ovaries of ewes at all periods of study except for the transition to anoestrus. With all scanning periods combined, daily numbers of 3mm follicles not growing further increased (P<0.05) between day 6 and 15 after ovulation in the CL-containing ovaries. Based on mean data for the whole periods of observation, the non-CL-bearing ovaries of ewes in the transition to anoestrus had fewer (P<0.05) follicles growing from 3 to > or =5mm in size before regression compared with the mid-breeding season and mid-anoestrus. The lifespan of follicles reaching > or =5mm in diameter was shorter (P < 0.05) in the CL- compared with non-CL-containing ovaries of anoestrous ewes induced to ovulate with GnRH ((6.5+/- 1.3) and (9.0+/- 1.0) days, respectively). Circulating concentrations of progesterone were lower during both transitional periods (into and out of anoestrus) and mid-anoestrus than during the mid-breeding season (P < 0.001), and were less during anoestrus than during both transitional periods (P < 0.05). It was concluded that CL/luteal structures locally suppressed the growth of ovarian antral follicles to the 3mm size-range except during the transition to anoestrus, but that there was no inhibitory effect of the CL on the growth of ovarian follicles to larger diameters. The presence of CL/luteal structures did not affect the length of the lifespan of follicles reaching > or =5mm in diameter nor the number of ovulations per ovary in cyclic ewes, but shortened large follicle lifespan in anoestrous ewes. Variations in peripheral concentrations of progesterone across the breeding season and between the breeding season and anoestrus did not alter the lifespan of large antral follicles. In the transition to anoestrus and during mid-anoestrus, the presence of the CL in an ovary appeared to maintain follicle development to ovulatory sizes and to increase the rate of turnover of large antral follicles, respectively.

Anestrus↗
PubMed2003

Effect of an asynchrony between ovulation and insemination on the results obtained after insemination with fresh or frozen sperm in rabbits.

The effects of the introduction of an 8-h asynchrony between ovulation and insemination on litter size components from rabbits were assessed. A total of 202 females belonging to a maternal line were used. Fresh and frozen sperm were used to perform the inseminations. Sperm was frozen with an extender composed of 1.75 M DMSO and 0.05 M sucrose. Four experimental groups were obtained depending on the type of sperm used (fresh or frozen) and on the moment that ovulation had been induced relative to the insemination (at the same time as insemination (t(0)) or 8 h before insemination (t(8))). Laparoscopy was performed on 12th day of pregnancy in pregnant females, and the ovulation rate, normal and total implanted embryos were noted. At kindling, total and live-born rabbits were noted. Results showed that better results were obtained after insemination with fresh semen than with frozen sperm (for females in the group t(0): 79% versus 61% fertility rate, 10.2 versus 6.4 normal implanted embryos and 8.1 versus 5.2 total number born, for fresh and frozen sperm, respectively). On the other hand, after the introduction of an 8-h asynchrony between ovulation and insemination, results were lower for both fresh (50% fertility rate, 7.5 normal implanted embryos and 5.7 total number born for the group of the asynchrony) and frozen sperm (31% fertility rate, 4.6 normal implanted embryos and 3.4 total number born for the group of the asynchrony). Although an approach between the moment of insemination and ovulation is justified when sperm survival could be compromised, results observed after the induction of an 8-h asynchrony were not those expected, perhaps due to the ageing of the oocytes before being fertilised, leading to both lack of fertilisation or early embryonic mortality.

Animals↗
PubMed2006

Rescue of corpus luteum function with peri-ovulatory HCG supplementation in IVF/ICSI GnRH antagonist cycles in which ovulation was triggered with a GnRH agonist: a pilot study.

Previous studies found a poor clinical outcome when a GnRH agonist (GnRHa) was used to trigger ovulation in GnRH antagonist IVF/ICSI cycles. This study aimed to determine the clinical and endocrine effects as well the optimal timing of HCG supplementation. Forty-five normogonadotrophic IVF/ICSI patients following a flexible antagonist protocol were prospectively randomized (sealed envelopes) to triggering of ovulation with a single bolus of either 10,000 IU of HCG (group 1, n = 15) or 0.5 mg buserelin s.c. In addition, the GnRHa triggered group was randomized into two groups: group 2 (n = 17) was supplemented with HCG 1500 IU, 12 h after ovulation induction and group 3 (n = 13) was supplemented with HCG 1500 IU 35 h after ovulation induction. Group 1 and group 3 had significantly higher luteal phase concentrations of progesterone (P < 0.001) as compared with group 2. Moreover, the clinical pregnancy rate of groups 1 and 3 was similar and significantly higher (P < 0.02) than that of group 2. A larger study, however, is required to substantiate these differences. No differences were seen regarding mid-luteal inhibin A concentrations between the three groups. Triggering of ovulation with GnRHa supplemented with 1500 IU HCG 35 h later (group 3) seems to secure a normal luteal phase and a normal clinical pregnancy outcome.

Chorionic Gonadotropin↗
PubMed1994

Effect of mifepristone on inhibition of ovulation and induction of luteolysis.

Mifepristone administration to women in the mid- or late follicular phase delays the luteinizing hormone (LH) surge and prolongs the follicular phase. Since the resumption of follicular growth commences following mifepristone cessation, the drug must be given either continuously or at repeated intervals in order to block ovulation. Using various regimens with or without exogenous progestins, ovulation was inhibited in the majority of subjects. However, this was not consistent and in several instances, LH surges and a rise in plasma progesterone were suggestive of ovulation and corpus luteum function. Therefore, mifepristone cannot be used as a contraceptive which will reliably inhibit ovulation. With low-dose mifepristone administration, alterations in endometrial morphology were characterized by a delay in maturation despite the presence of ovulation. This suggests that the endometrium displays a greater sensitivity to mifepristone than does the pituitary, a finding that may have important contraceptive implications. Late luteal-phase mifepristone administration to women who were not sexually active did not alter their menstrual rhythm, bleeding patterns or steroid and gonadotrophin concentrations. However, when used in unprotected women in the late luteal phase, mifepristone did not uniformly terminate all pregnancies. On the other hand, when used within 72 h of intercourse, mifepristone was as effective a post-coital agent as the standard high-dose oestrogen-progestin combination.

Abortion, Induced↗