An oocyte donation protocol using the GnRH antagonist ganirelix acetate, does not compromise embryo quality and is associated with high pregnancy rates.

PURPOSE: To evaluate the effect of the GnRH antagonist, ganirelix acetate, on oocyte quality. METHODS: Stimulation characteristics, implantation rates and clinical pregnancy rates were compared between 29 oocyte donors 21-31 years of age who underwent 31 cycles of ovarian stimulation with gonadotropins and ganirelix acetate, and 36 infertile couples of similar age range who underwent 51 cycles of ovarian stimulation using the same protocol. RESULTS: A significantly lower number of embryos were transferred in the donor/recipient group as compared to the infertile group (2.32+/-0.54 vs. 2.82+/-0.71, P<0.05). In contrast, implantation and clinical pregnancy rates per transfer, were significantly higher in the donor/recipient group (38.1% vs. 10.4%, P<0.01) and (61.3% vs. 23.1%, P<0.05) respectively, as compared to the infertile group. CONCLUSIONS: Incorporation of ganirelix acetate for pituitary suppression in stimulation protocols for oocyte donation is associated with high pregnancy rates suggesting that ganirelix acetate does not exert an adverse effect on oocyte or embryo quality.

The human pluripotent stem cell: impact on medicine and society.

OBJECTIVE: To discuss the current state of the science surrounding human pluripotent stem cells and to show that the derivation of such cells from donated preimplantation human embryos should be eligible for federal funding provided that certain protections are met. DESIGN: A literature search focusing on the scientific aspects of pluripotent stem-cell research and analyses of current and past legislation and federal panel recommendations. CONCLUSION(S): The current federal laws regulating the permission necessary to obtain fetal tissue from elective pregnancy terminations are intended to insulate the decision to terminate a pregnancy from the potential positive influence of fetal tissue transplantation. A similar situation can be created for the derivation of cells from excess preimplantation human embryos produced by IVF programs. If, as in fetal tissue research, assurances can be made that the research will have no influence on the decision to dispose of the embryo, the derivation of pluripotent stem cells from embryo should proceed with federal funding.

Clinical significance of the qualification of atypical squamous cells of undetermined significance: An analysis on the basis of histologic diagnoses.

OBJECTIVE: This study was undertaken to evaluate the significance of further qualification of atypical squamous cells of undetermined significance in routine Papanicolaou smears. STUDY DESIGN: A retrospective medical records review was conducted on 316 women whose Papanicolaou smears yielded diagnoses of either atypical squamous cells of undetermined significance suggestive of the presence of an intraepithelial lesion or atypical squamous cells of undetermined significance suggestive of a reactive process. RESULTS: The overall incidence of a squamous intraepithelial lesion (cervical intraepithelial neoplasia grades I, II, and III) was higher in the group with atypical squamous cells of undetermined significance suggestive of the presence of an intraepithelial lesion than in the group with results suggestive of a reactive process (41.1% vs 22.3%; P =.0344). Women with atypical squamous cells of undetermined significance suggestive of the presence of an intraepithelial lesion were 9.7 times more likely to have high-grade squamous intraepithelial lesion (cervical intraepithelial neoplasia III) develop than were women with atypical squamous cells of undetermined significance suggestive of a reactive process (95% confidence interval, 1.26-74.64). The incidence of high-grade squamous intraepithelial lesion was higher among women 35 years old (17.8% vs 6.3%; P =.0378). CONCLUSION: Women with a diagnosis of atypical squamous cells of undetermined significance suggestive of the presence of an intraepithelial lesion are more likely to have intraepithelial lesions develop than are those with atypical squamous cells of undetermined significance suggestive of a reactive process. Aggressive evaluation of cases of atypical squamous cells of undetermined significance suggestive of the presence of an intraepithelial lesion with colposcopy and cervical biopsies may be appropriate. Age should be considered as an independent factor in the plan of management.

Day 4 estradiol levels predict pregnancy success in women undergoing controlled ovarian hyperstimulation for IVF.

OBJECTIVE: To evaluate the usefulness of serum estradiol levels obtained on the fourth day of gonadotropin stimulation in predicting the likelihood of pregnancy during controlled ovarian hyperstimulation (COH) using luteal phase leuprolide acetate (LA). DESIGN: A 4-year retrospective analysis of day 4 estradiol levels and subsequent clinical pregnancy and delivery rates. SETTING: A university hospital tertiary referral center. PATIENT(S): Couples undergoing IVF treatment. MAIN OUTCOME MEASURE(S): Primary outcome measures included clinical pregnancy and delivery rates. Secondary outcome measures included the number of oocytes retrieved and the number of embryos available for transfer per COH cycle. RESULT(S): The clinical pregnancy and delivery rates for cycles with day 4 estradiol levels of >75 pg/mL were 42.3% (30/71) and 32.4% (23/71), respectively. These rates differed significantly from those for cycles with day 4 estradiol levels of < or = 75 pg/mL, which were only 9.1% (4/44) and 6.8% (3/44), respectively. The number of oocytes retrieved and the number of embryos available for transfer for cycles with day 4 estradiol levels of >75 pg/mL also differed significantly from those for cycles with day 4 estradiol levels of < or = 75 pg/mL (11.4 and 7.8 versus 6.8 and 4.3, respectively). CONCLUSION(S): Estradiol levels obtained on the fourth day of gonadotropin therapy are highly predictive of successful ovulation induction and pregnancy outcome in cycles using luteal phase LA.

Effects of a gonadotropin-releasing hormone analog on rabbit ovarian function.

This study was undertaken to elucidate the effects of a GnRH analog (GnRH-a) on rabbit ovulation, oocyte maturation, and steroidogenesis, and to verify whether treatment with a GnRH-a interferes with ovarian response to exogenous gonadotropin (hCG), both in vivo and in vitro. Three approaches were used. In the first, adult New Zealand White (NZW) rabbits were divided into two groups. Both received PMSG and hCG administered 72 h after PMSG. In the test group a GnRH-a, leuprolide acetate (LA; 20 microg/kg) was administered s.c. every 24 h. Treated rabbits showed a significant decrease in ovulatory efficiency (control = 88%; treated = 72%), and an increase in degeneration rate of preimplantation embryos (control = 30% vs. treated = 40%). For the second approach, in vitro perfusion experiments were designed to compare the direct effects of LA (10.000 ng/ml) and hCG (50 IU) on ovarian function and to verify whether the presence of a GnRH-a in the perfusate modifies the actions of hCG. LA reduced the ovulatory efficiency of hCG-treated ovaries perfused in vitro (hCG-treated = 87%; hCG-treated LA-perfused = 70%), reduced the potential for preimplantation development (morula stage: hCG-treated = 53%; hCG-treated LA-perfused = 31%; LA-perfused = 12%), and increased the degeneration rate of early embryos (21%, 48%, and 56% respectively). In the third approach, the direct effect of LA (Group I: control, Group II:1.000 ng/ml, and Group III:10.000 ng/ml) on the in vitro maturation of denuded rabbit oocytes was evaluated. LA induced meiotic maturation, but increased oocyte degeneration rate. The potential for preimplantation development was reduced (Morula stage: control = 16%, Group II = 8%, and Group III = 6%), and degeneration rate was increased (38%, 65%, 63% respectively). This study suggests that pharmacological doses of LA may exert a negative effect on oocyte function by direct action on the oocyte, indirectly via alteration of the intrafollicular environment and/or through interference with gonadotropin-induced biological effects within the ovary.

Effects of acetylsalicylic acid (aspirin) and naproxen sodium (naproxen) on ovulation, prostaglandin, and progesterone production in the rabbit.

OBJECTIVE: To determine the effects of acetylsalicylic acid (aspirin) and naproxen sodium (naproxen) on ovulation, ovarian prostaglandins (PG), and P production in the rabbit via in vivo and in vitro studies. DESIGN: Aspirin and naproxen were administered i.v. 6.5 and 7 hours, respectively, after hCG administration to New Zealand White adult female rabbits. Laparotomy was performed 24 hours after hCG administration. For in vitro experiments, control animals underwent laparotomy 6.5 (aspirin) and 7 hours (naproxen) after hCG administration. The treated animal received aspirin and naproxen; laparotomy was performed 1 hour later. One ovary was perfused for 6 hours with aspirin or naproxen whereas the contralateral ovary served as a control and was perfused with control medium (M199; GIBCO, Grand Island, New York). Perfusate samples were collected at 1-hour intervals for PG and P determination. SETTING: A conventional laboratory setting. INTERVENTIONS: In vivo experiments used i.v. administration of 100 mg/kg aspirin and 10 and 50 mg/kg naproxen. In vitro perfusion was also carried out with 100 micrograms/mL aspirin and 10 and 50 micrograms/mL naproxen added to the perfusate. MAIN OUTCOME MEASURES: Ovulatory efficiency (no. of ovulations/no mature follicles) and ovarian vein PG and P concentration were determined. RESULTS: Ovulatory efficiency was 88% for control, 41% for in vivo aspirin-treated, and 40% (10 mg/kg) and 0% (50 mg/kg) for naproxen-treated rabbits. Aspirin and naproxen were associated with decreased ovulatory efficiency when administered in vitro to both in vivo control and in vivo treated ovaries (control-medium = 70%; control-aspirin = 14%; aspirin-medium = 34%; aspirin-aspirin = 0%; control-naproxen = 25%; naproxen-medium = 38%; naproxen = 0% with 10 microgram/mL, and control-naproxen = 13%; naproxen-medium = 0%; naproxen = 0% with 50 micrograms/mL). Prostaglandin F2 alpha was undetectable in the perfusate of those ovaries perfused of those ovaries perfused either with aspirin or naproxen. Ovarian venous concentration of P in the perfusate was similar in all groups. CONCLUSIONS: Aspirin and naproxen significantly reduced ovulatory efficiency and PG production both in vivo and in vitro in hCG-treated rabbits. A critical period of 6.5 and 7 hours after hCG administration was established.

Role of calcium/calmodulin-dependent protein kinase II in gonadotrophin-induced ovulation in in vitro perfused rabbit ovaries.

The objectives of these experiments were to determine (i) the role of calcium/calmodulin-dependent protein kinase II-mediated signal transduction in hCG-induced ovulation and (ii) whether there is an association between arachidonic acid metabolites, nitric oxide and calcium/calmodulin-dependent protein kinase II in the overall scheme of ovulation induction. Ovarian arteries were cannulated in situ, and the ovaries were excised and perfused in vitro. Ovulatory efficiency ([number of ovulated follicles/number of mature follicles > 1.5 mm] x 100) was calculated for each experiment. Calcium/calmodulin-dependent protein kinase II substrate induced ovulation in the absence of gonadotrophin (calcium/calmodulin-dependent protein kinase II substrate: 66.3%; control: 0%). In the next experiment, perfusion medium of the experimental ovary was supplemented with KN 62, a potent inhibitor of calcium/calmodulin-dependent protein kinase II, while the contralateral ovary served as control. Ovulations were induced in both ovaries with hCG (50 iu (150 ml)-1) and perfusion was continued for 8 h. In the third experiment, ovaries were perfused with prostaglandin F2 alpha (PGF2 alpha) with and without KN 62, while the contralateral ovary was perfused with medium alone. KN 62 reduced the ovulatory efficiency of hCG-treated ovaries in vitro during perfusion (hCG + 10(-7) mol KN 62 l-1: 32.9%; hCG: 80.9%). Furthermore, it significantly reduced the ovulatory efficiency of PGF2 alpha-treated ovaries (PGF2 alpha + KN 62 = 21.5%; PGF2 alpha = 59.9%).(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of gonadotrophin-induced ovulation in rabbits by perfusion with dibutyryl cAMP via reduction of ovarian prostaglandin production.

The role of cAMP in ovulation, oocyte maturation and prostaglandin production was assessed using a rabbit ovary preparation perfused in vitro. Dibutyryl cAMP (10(-3), 10(-4) or 10(-5) mol l-1) was added to the perfusate of one ovary. The contralateral, control ovary was perfused with medium alone. Thirty minutes after the onset of perfusion, 50 iu hCG was added to the perfusate of all ovaries. Dibutyryl cAMP inhibited hCG-induced ovulation in a dose-related fashion. No difference in ovum maturity or degeneration was found between control ovaries and ovaries treated with dibutyryl cAMP. Ovarian progesterone production was not affected by exposure to dibutyryl cAMP. The concentrations of 6-keto PGF1 alpha (the stable metabolite of prostacyclin) and PGF2 alpha in the perfusate of ovaries treated with dibutyryl cAMP were 49.6% and 32.0% of the control values, respectively, 12 h after hCG administration. Inhibition of 6-keto PGF1 alpha production by dibutyryl cAMP was dose related. Production of PGE2 was unaffected by dibutyryl cAMP. These data raise the possibility that continuous exposure to dibutyryl cAMP may inhibit hCG-induced ovulation in the perfused rabbit ovary via a reduction in PGF2 alpha and prostacyclin production.

Effect of interleukin-1 beta on ovulation in the in vitro perfused rabbit ovary.

Interleukin-1 (IL-1), a prominent 17-kilodalton member of a group of immune mediators referred to as cytokines, is secreted by a variety of immuno- and nonimmunocompetent cells. As IL-1 is an established mediator of inflammation, and ovulation may constitute an inflammatory-like reaction, consideration may be given to the possibility that IL-1 may play an intermediary role in the ovulatory process. Such a hypothesis is supported by the recent demonstration of the gonadotropin-dependent preovulatory induction of IL-1 transcripts at the level of the murine and human ovary. To date, however, the direct effect of IL-1 beta on the ovulatory process has not been examined. The objective of this study was to investigate the potential role of IL-1 beta in ovulation, oocyte maturation (nuclear and cytoplasmic), and subsequent fertilizability of in vitro ovulated oocytes. Rabbit ovaries perfused in vitro were used for these experiments. Ovarian arteries were cannulated in situ, and the ovaries were excised and perfused in vitro with or without IL-1 beta (18 ng/ml). The ovulatory efficiency of 18 ng/ml IL-1 beta-treated ovaries was 73.1%, similar to that of hCG (71.2%). Recovered oocytes were examined for their maturation and were inseminated in vitro to investigate fertilization, cleavage, and embryonic development. The fertilization rates of the 18 ng/ml IL-1 beta-treated and hCG-treated groups were 65.8% and 95.8% (P < 0.01), respectively. Cleavage rates of the IL-1 beta-treated and hCG-treated groups were 50% and 83.3% (P < 0.01), respectively. Most of the cleaved embryos from the IL-1 beta-treated group arrested at the four-cell stage, and only 2.6% of the fertilized embryos developed into the morula stage, whereas 54.2% of the hCG-treated group developed to the morula stage (P < 0.01). A cytotoxic effect of IL-1 beta is unlikely in this model. A more likely explanation is the induction of other factors by IL-1 beta, which may inhibit cytoplasmic maturation. Taken together, our findings demonstrate that in the absence of an ovulatory gonadotropic trigger, IL-1 beta can induce ovulation and oocyte maturation, facilitate fertilization, and influence subsequent embryonic development. Although fertilization and embryonic development occurred after IL-1 beta treatment, these rates were lower than those after hCG treatment. These observations give credence to the possibility that IL-1 may play an intermediary role in the ovulatory process.

The role of protein kinase-C in gonadotropin-induced ovulation in the in vitro perfused rabbit ovary.

Tumor-promoting phorbol esters are believed to affect ovarian granulosa cell progesterone and prostaglandin (PG) production and possibly ovulation by activating protein kinase-C (PKC). The effects of phorbol esters and PKC inhibitors on ovulation, progesterone, and PG production were examined in an in vitro perfused rabbit ovary. The effect of tranexamic acid, an inhibitor of the conversion of plasminogen activator to plasmin, on phorbol ester-induced ovulation was also examined. Phorbol 12,13-dibutyrate (PdBU), a PKC stimulator, induced ovulation in a dose-related manner in the absence of gonadotropins (56%, 200 nM PdBU; 0%, 0 nM PdBU; P < 0.05). Perfusate progesterone levels were increased only after 600 nM PdBU treatment, and perfusate PGF2 alpha, PGE2, and 6-keto-PGF1 alpha were increased in a dose-dependent fashion (P < 0.05). Staurosporine, a potent inhibitor of the catalytic domain of PKC, and calphostin-C, a specific inhibitor of the diacylglycerol-binding region, inhibited hCG-induced ovulation in a dose-related manner. Gonadotropin-induced ovulation decreased from 73% without staurosporine to 19% with 1.0 microM staurosporine (P < 0.01). Calphostin-C reduced ovulatory efficiency from 60% to 24% (P < 0.01). However, neither inhibitor decreased progesterone or PGF2 alpha production by ovaries exposed to hCG. hCG-induced oocyte maturation was also unaffected by exposure to either staurosporine or calphostin-C. Tranexamic acid reduced phorbol ester-induced ovulatory efficiency from 67% to 37% (P < 0.05). These findings demonstrate that the calcium-dependent PKC pathway is instrumental in gonadotropin-mediated follicular rupture in the rabbit. Although PGs may play an important role in ovulation, they do not appear to be directly responsible for PKC-mediated follicular rupture.

Superoxide dismutase activity, lipid peroxide production and corpus luteum steroidogenesis during natural luteolysis and regression induced by oestradiol deprivation of the ovary in pseudopregnant rabbits.

The relationship of oxygen free radicals to corpus luteum function in rabbits was explored during various stages of pseudopregnancy, including natural and induced luteal regression. Induced luteolysis was achieved during mid-pseudopregnancy by removal of an oestradiol capsule placed at the onset of pseudopregnancy, which suppressed ovarian oestradiol production. Activity of manganese superoxide dismutase (Mn SOD) was significantly and positively correlated with ovarian progesterone production (P < 0.01) throughout pseudopregnancy and during natural regression. Oestradiol deprivation for 12, 24 or 72 h resulted in declines in Mn SOD activity and progesterone secretion, although Mn SOD rose and corpus luteum steroidogenesis was restored to normal when the capsule was replaced for 48 h before assessment, having been removed for 24 h. Lipid peroxide and progesterone concentrations were not correlated, although a significant rise in lipid peroxides in the luteal tissue was detected after deprivation of oestradiol for 72 h. Changes in progesterone production and Mn SOD activity were not associated with alterations in concentration of prostaglandin F metabolite. These data suggest that Mn SOD may be involved in regulating function of the corpus luteum during pseudopregnancy in rabbits and that oxygen free radicals may play a role in regression of corpus luteum in this species.

Changes in rabbit corpus luteum progesterone secretion and cellular morphology following unilateral luteectomy or ovariectomy.

The objective of this study was to determine whether removal of corpora lutea (CL) from one ovary (unilateral luteectomy; ULL) or removal of the entire ovary (unilateral ovariectomy; ULO) of pseudopregnant rabbits would cause compensatory growth and progesterone production by the contralateral ovary. Pseudopregnancy was induced in rabbits with hCG (Day 0). On the first day of pseudopregnancy, one group of rabbits received a sham operation (controls), another group underwent ULL, and a third group underwent ULO. On Day 11 of pseudopregnancy, each rabbit underwent laparotomy, the ovarian artery and vein were cannulated, and the ovary(ies) was removed and perfused in vitro for 6 h. The mean CL weight increased by 33% in the ULL group and by 28% in the ULO group as compared to sham-operated controls. Peripheral estradiol and progesterone levels in sham-operated control, ULL, and ULO groups were similar. Ovarian venous estradiol levels were similar in the control and ULL groups, but were significantly increased in the remaining ovary of the ULO group. Both ovarian venous progesterone in vivo and progesterone secretion in vitro increased significantly in contralateral ovaries from ULL and ULO rabbits as compared to sham-operated controls. Progesterone secretion by ovaries perfused in vitro increased significantly in the contralateral ovary of the ULL and ULO groups. Mean number of luteal cells per CL increased significantly in the ULL group, but not in the ULO group. In contrast, luteal cell volume increased significantly in the ULO, but not in the ULL group. The stimuli responsible for increased progesterone production following ULL and ULO result in morphological changes in the remaining CL.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidermal growth factor inhibits follicular response to human chorionic gonadotropin: possible role of cell to cell communication in the response to gonadotropin.

Epidermal growth factor (EGF) affects follicular steroidogenesis and expression of gonadotropin receptors. The effects of EGF on hCG-induced estradiol and progesterone secretion and ovulation were examined in the in vitro perfused rabbit ovary. We also examined the effects of EGF on hCG-induced progesterone secretion by isolated granulosa cells. In addition, distribution of hCG within the follicle was probed by immunohistochemical means 30 min after its administration to the in vitro perfused ovary. EGF significantly (P less than 0.05) reduced hCG-induced secretion of estradiol (control, 117 +/- 12 pg/min.follicle; 10 ng/ml EGF, 55 +/- 10) and progesterone (control, 18.2 +/- 1.2 ng/min.follicle; 10 ng/ml EGF, 11.9 +/- 0.8) by the perfused ovary. In contrast, EGF did not inhibit hCG-induced progesterone secretion by isolated granulosa cells. Ovulatory efficiency (number of ovulated ova per number of mature follicles x 100) when EGF was given 30 min before hCG was reduced dose-dependently from 58.2% with no EGF to 8.3% with 10 ng/ml EGF (P less than 0.001). Ovulation was not inhibited by EGF when it was given 30 min after hCG. Distribution of hCG in the preovulatory follicle was confined to the basement membrane, thecal cell layer, and a small fraction of the outer granulosa cell layer. These observations suggest that gonadotropin stimulates the follicle through the release of a secondary signal(s) from ligand-bound granulosa cells near the follicle wall to unexposed cells of the inner avascular area. EGF may inhibit the follicular response to hCG by attenuation of this cell to cell communication.

Effects of intravenous cocaine on reproductive function in the mated rabbit.

A dramatic increase in the use of crack cocaine by young women has resulted in the exposure of a substantial number of fetuses to the drug in utero. The goal of these experiments was to investigate the effects of intravenous cocaine (a model for crack) on reproductive function in the female rabbit. We used two protocols: (1) single daily injections over the course of pregnancy ("single daily" protocol), with animals examined on day 1, 8, 15, 22, or 29, and (2) six hourly injections on the day of mating ("binge" protocol). The maximum tolerated dose of cocaine, 4 mg/kg, was administered at 0.5 ml/min. The single daily protocol increased ovulation but had no effect on fetal and placental weights or preterm delivery. The binge protocol significantly reduced in vitro development of retrieved embryos but did not affect implantation assessed on day 8 of pregnancy.

Estradiol regulation of the rabbit corpus luteum: in vivo and in vitro studies.

The objective of this study was to determine whether estradiol has a direct effect on progesterone secretion by the rabbit corpus luteum. Empty or estradiol-filled Silastic capsules were implanted sc into pseudopregnant rabbits (day 0). Ten days later (day 10), peripheral blood was obtained via the marginal ear vein, and Silastic capsules were removed. Twenty-four hours after capsule removal (day 11), blood samples were obtained and ovaries removed for in vitro perfusion. The artery and vein of each ovary were individually cannulated, and ovaries were perfused in vitro for 6 h. Mean progesterone secretion rates were determined from perfusate samples taken every 30 min. On day 10, serum progesterone concentrations were similar in control and estradiol-treated animals. On day 11, 24 h after withdrawal of Silastic capsules, serum progesterone concentration in the estradiol-treated rabbits decreased significantly compared to controls. The withdrawal of estradiol also significantly reduced the secretion of progesterone by in vitro perfused ovaries in estradiol-withdrawn rabbits compared to empty capsule controls. Addition of estradiol or 25-hydroxycholesterol (25-OH) to the perfusion medium significantly increased progesterone secretion by ovaries from estradiol-withdrawn rabbits but not to control values. In contrast, a combination of estradiol plus 25-OH restored progesterone secretion to control levels. Although estradiol together with 25-OH stimulated progesterone secretion 24 h after estradiol withdrawal, progesterone secretion in vitro was unaffected 48 h after capsule removal, whereas pregnenolone stimulated secretion 5-fold. These results demonstrate that estradiol has a direct and acute stimulatory effect on progesterone secretion by the rabbit corpus luteum.

Do prostaglandins lead to ovulation in the rabbit by stimulating proteolytic enzyme activity?

OBJECTIVE: To determine if prostaglandins (PGs) have a direct effect on the ovarian proteolytic enzyme system by examining ultrastructure of the follicle wall and the microvasculature in the presence and absence of indomethacin and by using the isolated perfused rabbit ovary. DESIGN: Nine hours after administration of human chorionic gonadotropin (hCG) or hCG plus indomethacin, follicles were removed and processed for scanning and transmission electron microscopy. Isolated perfused rabbit ovaries were induced to ovulate with PGF2 alpha (100 ng/mL) in the presence and absence of tranexamic acid (0.1, 1.0, or 10 mM), a plasminogen activator inhibitor. RESULTS: The addition of indomethacin to hCG inhibited ovulation and production of PGs without affecting the follicular microvasculature. However, the changes in follicle wall architecture were less pronounced after treatment with indomethacin. Ovulatory efficiency in response to PGF2 alpha (the percent of follicles greater than 1.5 mm that ovulate) was significantly reduced (P less than 0.01) by 10 mM tranexamic acid. CONCLUSIONS: These results suggest that PGs induce follicular rupture by activation of proteolytic enzymes located in the follicle wall.

Effect of inhibition of oxygen free radical on ovulation and progesterone production by the in-vitro perfused rabbit ovary.

The potential role of oxygen free radicals in hCG-induced ovulation was investigated using the free radical scavenging enzymes superoxide dismutase (SOD) and/or catalase with the in-vitro perfused rabbit ovary preparation. SOD (25 micrograms/ml) and SOD + catalase (25 micrograms/ml) significantly reduced the % of large follicles that ovulated during perfusion (P less than 0.005). Neither maturity nor degeneration of ovulated ova and follicular oocytes was affected by SOD and/or catalase. Progesterone concentration in the perfusate was significantly increased in the SOD + catalase treatment group (P less than 0.01). These results indicate a significant role for oxygen free radicals in the process of ovulation.