The in vivo and in vitro effects of clomiphene citrate on ovulation, fertilization, and development of cultured mouse oocytes

Between innovation and precaution: how did offspring safety considerations play a role in strategies of introducing new reproductive techniques?

The field of reproductive medicine has been criticized for introducing ARTs without systematic research on possible safety risks and for failing to meet the standards of evidence-based innovation held elsewhere in medicine. In this paper, firstly, we ask whether ‘responsible innovation’ has been a concern for the field, and if so, how it has understood the practical implications of this idea for the development and introduction of potentially risky new ARTs. Secondly, we consider whether the field has indeed fallen short of its responsibilities in this respect, and if so, how things can be improved. To answer these questions, we present three case studies involving the introduction of a new reproductive technology: ICSI, preimplantation genetic testing and mitochondrial replacement therapy. As a framework for analyzing these cases, we used Per Sandin’s account of the four dimensions of dealing with risks (threat, uncertainty, action, command) that are central to debates about the possible role of the so-called precautionary principle. We conclude that, although offspring safety concerns have been on the agenda of the debate about bringing the relevant technologies to the clinic, systematic safety and effectiveness studies were not always conducted. As professionals in assisted reproduction have a responsibility to take account of the welfare of the children they are creating, we suggest a policy of proceeding with systematic caution. Legal measures may be needed to ensure that professional guidance is followed in practice. Finally, an open question concerns the threshold for acceptable risk in the context of introducing new ARTs. Multiple stakeholders, including professional societies and patient organizations, should have a role in the urgent debate about this.

Comparative study of fertilization rates of C57BL/6NKorl and C57BL/6N mice obtained from two other sources

C57BL/6N is the most widely used inbred mouse strain applied in a wide variety of research areas including cancer, cardiovascular biology, developmental biology, diabetes and obesity, genetics, immunology, neurobiology, and sensorineural research. To compare the fertilization rates of C57BL/6NKorl mice with two commercial C57BL/6N stocks, differences in reproductive organ structures, sperm and egg numbers, fertilization rates, and embryo development rates among C57BL/6NKorl (Korea FDA source), C57BL/6NA (USA source), and C57BL/6NB (Japan source) mice were determined. Among the stocks, no significant differences were detected in organ weight and histological structure of male and female reproductive organs, although body weight was higher in C57BL/6NKorl mice than that in the other groups. The concentration and morphology of sperm and eggs in C57BL/6NKorl mice were similar to those of C57BL/6NA and C57BL/6NB mice. Furthermore, the three stocks had similar in vitro fertilization and embryo development rates, although these rates tended to be higher in C57BL/6NB mice. Pup body weight was higher in C57BL/6NKorl and C57BL/6NB mice than that in C57BL/6NA mice. The results of the present study suggest that C57BL/6NKorl, C57BL/6NA, and C57BL/6NB mice obtained from three different sources have similar fertilization and embryo development rates, although there were slight differences in the magnitude of their responses rates.

Aromatase Inhibition Reduces the Dose of Gonadotropin Required for Controlled Ovarian Hyperstimulation

OBJECTIVE

To compare the use of the aromatase inhibitor, letrozole, in conjunction with follicle-stimulating hormone (FSH) injection, and FSH alone for controlled ovarian hyperstimulation (COH) in patients with polycystic ovarian syndrome (PCOS) or ovulatory infertility.

METHODS

This nonrandomized study included two study groups: 26 patients with PCOS and 63 with ovulatory infertility (unexplained infertility [41 patients], male factor infertility [17 patients], and endometriosis [5 patients]), who received letrozole in addition to FSH; and two control groups: 46 PCOS patients and 308 with ovulatory infertility (unexplained infertility [250 patients], male factor infertility [42 patients], and endometriosis [16 patients], who received FSH only. All patients had intrauterine insemination (IUI). Main outcome measures included dose of FSH used per cycle, number of preovulatory follicles greater than 16 mm in diameter, cancellation rate, and pregnancy rate.

RESULTS

The FSH dose required for ovarian stimulation was significantly lower when letrozole was used in both study groups compared to the control groups without a significant difference in number of follicles greater than 16 mm. IUI cancellation rate was significantly lower with letrozole treatment in PCOS patients. In women with PCOS, clinical pregnancy rate per completed IUI cycle was 26.5% in the letrozole plus FSH group versus 18.5% in the FSH-only group. In ovulatory infertility patients, the pregnancy rate was similar in both study and control groups (11%).

CONCLUSION

We believe that inhibition of estrogen synthesis by aromatase inhibition will release the estrogenic negative feedback, resulting in an increase in endogenous FSH secretion. Moreover, by inhibiting conversion of androgens into estrogens, accumulating androgens may increase follicular sensitivity to FSH. Such a protocol has the potential to lower FSH treatment cost and may improve response for low responders who require high FSH doses during ovarian stimulation.

Understanding fertilization through intracytoplasmic sperm injection (ICSI)

Since the establishment of in vitro fertilization, it became evident that almost half of the couples failed to achieve fertilization and this phenomenon was attributed to a male gamete dysfunction. The adoption of assisted fertilization techniques particularly ICSI has been able to alleviate male factor infertility by granting the consistent ability of a viable spermatozoon to activate an oocyte. Single sperm injection, by pinpointing the beginning of fertilization, has been an invaluable tool in clarifying the different aspects of early fertilization and syngamy. However, even with ICSI some couples fail to fertilize due to ooplasmic dysmaturity in relation to the achieved nuclear maturation marked by the extrusion of the first polar body. More uncommon are cases where the spermatozoa partially or completely lack the specific oocyte activating factor. In this work, we review the most relevant aspects of fertilization and its failure through assisted reproductive technologies. Attempts at diagnosing and treating clinical fertilization failure are described.

Intrauterine insemination in natural cycle may give better results in older women

BACKGROUND

Controlled ovarian hyper-stimulation (COH) in combination with intrauterine insemination (IUI) has been shown to result in significantly higher pregnancy rates compared to un-stimulated (natural cycle) IUI. This may however not be true in all ages.

METHODS

We performed a retrospective cohort study and analysed data collected prospectively on 1759 IUI cycles in couples with unexplained infertility. The results were analysed to show the outcome of IUI with COH, and IUI in natural cycle (unstimulated), in younger women compared to their older counterparts.

RESULTS

In women age 37 and younger, COH resulted in a significantly higher pregnancy rate (13.0% vs 6.5%) and live-birth rate (10.7% vs 5.2%) compared to natural cycle IUI (p = 0.025, p = 0.045 respectively). However for older women age >37 years, natural cycle (unstimulated) IUI, resulted in a significantly higher pregnancy rate (12.0% vs 8.5%) live-birth rate (7.5%vs 3.5%) than IUI with COH ((p = 0.0037). This difference is even more significant when COH was performed with clomiphene citrate (7.5% vs 2.1%) (p = 0.0017).

CONCLUSION

COH was associated with a lower live birth rate in older women, irrespective of the agent used, and it seems to be worse when the anti-oestrogenic drug clomiphene citrate was used for COH. Older women may benefit more from natural cycle (unstimulated) IUI. A randomised controlled trial is required to confirm this observation.

Comparison of the efficacy of the aromatase inhibitor letrozole and clomiphene citrate as adjuvants to recombinant follicle-stimulating hormone in controlled ovarian hyperstimulation: a prospective, randomized, blinded clinical trial

OBJECTIVE

To study the efficacy of the aromatase inhibitor letrozole as adjuvant to recombinant FSH (rFSH) in controlled ovarian hyperstimulation (COH).

DESIGN

Prospective, randomized, and blinded clinical study.

SETTING

Academic tertiary institute.

PATIENT(S)

Forty-one patients with unexplained infertility undergoing intrauterine insemination (IUI) therapy were randomized to receive either letrozole or clomiphene citrate (CC) as adjuvants to rFSH.

INTERVENTION(S)

From day 3 to 7 of the cycle 2.5 mg/d letrozole or 100 mg/d CC were administrated. All patients received 75 IU rFSH starting on day 7 of stimulation until the day of hCG administration. Ovulation was triggered with recombinant hCG (250 microg) when the leading follicle(s) reached 18 mm in diameter. A single IUI was performed 36 hours later. The luteal phase was supplemented with micronized progesterone vaginally.

MAIN OUTCOME MEASURE(S)

Ovarian stimulation response (E(2) levels and number of follicles) was our primary outcome.

RESULT(S)

There were no differences in demographic characteristics between groups. Although there was a significantly lower peak serum E(2) level in the group receiving letrozole + rFSH compared with CC + rFSH (914 +/- 187 vs. 1,207 +/- 309 pg/mL, respectively; P<.007), there were no differences in the number of mature (>16 mm) preovulatory follicles. A significantly higher endometrial thickness was observed at the time of hCG administration in patients that received letrozole (9.5 +/- 1.5 mm vs. 7.3 +/- 1.1 mm; P=.0001). The clinical pregnancy rate was similar between groups (23.8% vs. 20%, respectively).

CONCLUSION(S)

The aromatase inhibitor letrozole appears to constitute a good alternative to CC in patients with unexplained infertility undergoing gonadotropin-stimulated COH cycles combined with IUI therapy.

Effects of metformin and clomiphene citrate on ovarian vascularity in patients with polycystic ovary syndrome

OBJECTIVE

To evaluate the effects of metformin and of clomiphene citrate (CC) on the ovarian blood perfusion and on perifollicular and peri-corpus luteum (CL) vascularity in anovulatory women with polycystic ovary syndrome (PCOS).

DESIGN

Prospective cohort study.

SETTING

University "Magna Graecia" of Catanzaro.

PATIENT(S)

Forty anovulatory nonobese patients with PCOS who ovulated under treatment with metformin (850 mg twice daily) plus placebo (metformin group) and 38 under placebo plus CC (150 mg for 5 days; CC group). Another 30 healthy normal cycled women (control group).

INTERVENTION(S)

Serial transvaginal ultrasonographic examinations.

MAIN OUTCOME MEASURE(S)

Ovary artery blood flow impedance, dimensions, and vascularization of the dominant follicle and of the CL.

RESULT(S)

No difference was observed in all parameters in metformin ovulating cycles in comparison with healthy controls. In CC ovulating cycles, ovarian artery impedance, and perifollicular and peri-CL vascularization the results were significantly different from the metformin and control groups. After grouping the stimulated cycles for reproductive outcomes, perifollicular vascularization alone ended up being significantly lower only in CC-stimulated cycles with unfavorable outcome.

CONCLUSION(S)

In patients with PCOS who ovulate under treatment with metformin, the ovarian blood flows are similar to those observed in healthy women, whereas CC administration reduces the ovarian and, specifically, the perifollicular vascularization.

Clomiphene citrate inhibits gonadotropin-induced ovulation by reducing cyclic adenosine 3',5'-cyclic monophosphate and prostaglandin E2 levels in rat ovary

OBJECTIVE

To determine whether clomiphene citrate (CC) inhibited gonadotropin-induced ovulation by reducing cyclic adenosine 3',5'-cyclic monophosphate (cAMP) and prostaglandin E2 (PGE2) levels in ovary. If so, to determine whether E2 coadministration could protect against these effects of CC.

DESIGN

A controlled prospective study.

SETTING

Laboratory research setting in the department of reproductive biomedicine at a national research institute in India.

ANIMAL(S)

Sixty sexually immature female rats that were 24-25 days of age.

INTERVENTION(S)

The sexually immature female rats were given a single injection (10 IU i.m.) of pregnant mare serum gonadotropin. After 48 hours, the rats were given single injections of hCG (10 IU) along with CC, with or without E2, for 16 hours.

MAIN OUTCOME MEASURE(S)

Number of superovulated COCs, ovary and uterus weight, FSH and LH levels in serum, and cAMP and PGE2 levels in ovary.

RESULT(S)

The superovulatory dose of gonadotropins significantly increased ovary and uterus weights, cAMP and PGE2 levels in ovary, and serum levels of FSH and LH. Coadministration of CC (10 mg/kg body weight) significantly reduced levels of cAMP, PGE2 in the ovary, ovary and uterus weights, and ovulation rate, whereas FSH and LH levels were not significantly altered. Supplementation of E2 protected against these inhibitory effects of CC and augmented levels of FSH and LH in serum.

CONCLUSION(S)

Clomiphene citrate inhibited gonadotropin-induced ovulation by reducing cAMP and PGE2 levels in the ovary, and E2 protected against these effects of CC on gonadotropin-induced ovulation in rat.

Estradiol protects clomiphene citrate–induced apoptosis in ovarian follicular cells and ovulated cumulus–oocyte complexes

OBJECTIVE

To determine whether clomiphene citrate (CC) reduces E(2) level in the ovary and circulation and induces apoptosis in ovarian follicular cells and ovulated cumulus-oocyte complexes (COCs). If yes, to determine whether E(2) coadministration could protect against these adverse effects of CC.

DESIGN

A controlled prospective study.

SETTING

Laboratory research setting.

ANIMAL(S)

Ninety sexually immature female rats that were 24-25 days of age.

INTERVENTION(S)

The immature female rats were injected with a single dose of 10 IU of pregnant mare serum gonadotropin. After 48 hours, 10 IU of hCG along with 10 mg of CC per kilogram of body weight, with or without 2.0 mg of E2 per kilogram of body weight were coadministered. After 16 hrs, the rats were killed; COCs were collected from oviduct and ovaries were isolated.

MAIN OUTCOME MEASURE(S)

Number of superovulated COCs, oocyte morphology, E2 level in ovary and serum, histology of ovary, DNA fragmentation, and bax protein expression in ovary and COCs.

RESULT(S)

The number of COCs and E2 level in ovary and serum were reduced, whereas membrane blebbing in oocytes, bax protein expression, and DNA fragmentation in ovarian follicular cells and ovulated COCs were induced after CC treatment. These adverse effects of CC were protected against if animals were coadministered with E2.

CONCLUSION(S)

Clomiphene citrate-induced apoptosis in ovarian follicular cells (probably granulosa cells), thereby reducing E2 level in ovary and circulation that might have resulted in poor development and maturation of oocytes leading to reduced ovulation.

Effect of repeated administration of clomiphene citrate at two different times on the endometrium in patients undergoing intrauterine insemination

Background, Aims and Methods:  Clomiphene citrate (CC) has been widely used for induction of ovulation; however, despite the high rate of ovulation, the pregnancy rate is only 30%. The anti-estrogenic effect of CC on the endometrium is one explanation for this finding. It is well known that repeated administration of CC enhances its anti-estrogenic effect. To overcome this adverse affect, a number of techniques have been used. One technique is the early administration of CC, in an attempt to decrease the anti-estrogenic effects of CC on the endometrium. The aim of the present study was to retrospectively evaluate if repeated administration of CC at varying times may affect the endometrium during preovulatory period; pregnancy rates were compiled for patients with unexplained infertility undergoing intrauterine insemination (IUI). The patients were divided into four groups based on the number of repeat administrations and the time of CC administration. Results:  The endometrial thickness at the day of human chorionic gonadotropin administration was greater in early administration within three consecutive CC cycles than the others. Conclusion:  When the endometrium is thin during classical administration of CC, it is worth attempting the early administration of CC in the CC/IUI treatment for patients with unexplained infertility. However, this effect disappeared over the duration of the three consecutive CC cycles. (Reprod Med Biol 2004; 3: 153-157).

Effects of letrozole on superovulation with gonadotropins in women undergoing intrauterine insemination

OBJECTIVE

To investigate the effects of letrozole in patients undergoing superovulation with gonadotropins and IUI.

DESIGN

Retrospective analysis.

SETTING

Academic teaching hospital.

PATIENT(S)

Women younger than 40 years of age with patent fallopian tubes and infertility of more than 1 year in duration who were undergoing IUI and gonadotropin therapy.

INTERVENTION(S)

Gonadotropins alone administered from day 3 or a combination of letrozole, 5 mg/d on day 3 to 7, and gonadotropins starting on day 5 of the menstrual cycle. Ultrasonography was performed before initiation of treatment, on day 9 of menstrual cycle, and as required thereafter until the dominant follicle reached 18 mm in diameter. Ovulation was triggered with 10,000 IU of hCG, and IUI was performed 24 and 48 hours later.

MAIN OUTCOME MEASURE(S)

Gonadotropin requirements, endometrial thickness, number of follicles, and pregnancy rate.

RESULT(S)

All 205 IUI treatment cycles conducted from March 2001 to March 2002 were included. Gonadotropins alone were used in 145 cycles and combination therapy was used in 60 cycles. Patients cotreated with letrozole required fewer gonadotropin administrations (median difference, 300 IU [95% confidence interval (CI), 225-375 IU]), developed more follicles larger than 14 mm (median difference, 1 follicle [95% CI, 1-2 follicles), and had a thinner endometrium (median difference, 1 mm [95% CI, 0.4-1.6 mm]). The pregnancy rate did not differ between patients using gonadotropin alone and those using gonadotropin plus letrozole (20.9% vs. 21.6%).

CONCLUSION(S)

The addition of letrozole to gonadotropins decreases gonadotropin requirements, increases the number of pre-ovulatory follicles and decreases endometrial thickness, without a negative effect on pregnancy rates.

Clomiphene citrate-induced perturbations during meiotic maturation and cytogenetic abnormalities in mouse oocytes in vivo and in vitro

OBJECTIVE

To determine if clomiphene citrate induces temporal perturbations during meiotic maturation and aneuploidy in mouse oocytes.

DESIGN

A controlled dose study involving mouse oocytes in vivo and in vitro.

SETTING

Clinical and academic research setting in a university medical center.

INTERVENTION(S)

Oocytes were obtained after superovulation and from mature follicles.

MAIN OUTCOME MEASURE(S)

Cytogenetic analysis of oocytes for aneuploidy, premature centromere separation, premature anaphase, and single chromatids, and the frequencies of metaphase I and diploid oocytes.

RESULT(S)

Clomiphene citrate resulted in a decrease in the number of ovulated oocytes and a significant (P<.05) increase in hyperploidy at 100 mg/kg in vivo. In vitro, 5.0 microg/mL of clomiphene citrate significantly (P<.05) increased hyperploidy and reduced the proportion of metaphase I oocytes.

CONCLUSION(S)

These findings suggest that clomiphene citrate has the potential for inducing aneuploidy in mouse oocytes both in vivo and in vitro and that the rate of oocyte maturation is altered after clomiphene exposure in vitro. Additional data are needed to support the results of this study.

Serum concentrations of enclomiphene and zuclomiphene across consecutive cycles of clomiphene citrate therapy in anovulatory infertile women

OBJECTIVE

To determine the serum concentrations of enclomiphene and zuclomiphene across consecutive cycles of clomiphene citrate treatment in anovulatory infertile women.

DESIGN

Prospective cohort.

SETTING

Tertiary institutional infertility clinic.

PATIENT(S)

Fourteen consenting anovulatory infertile women receiving standardized, cyclic, incremental treatment with clomiphene citrate for ovulation induction.

INTERVENTION(S)

Clomiphene citrate treatment (50-150 mg/d, cycle days 5-9), titrated to the minimum effective ovulation-inducing dose, was administered for three to six total cycles. Blood samples were obtained on cycle days 3 and 10 in each treatment cycle.

MAIN OUTCOME MEASURE(S)

Serum concentrations of enclomiphene and zuclomiphene.

RESULT(S)

Cycle day 3 zuclomiphene levels were below assay limits in all initial cycles, increased progressively across three consecutive cycles, and thereafter plateaued. Cycle day 3 enclomiphene concentrations were uniformly undetectable. Cycle day 10 enclomiphene levels increased with dose administered, but these observations were not statistically significant.

CONCLUSION(S)

Clomiphene citrate induction of ovulation results in an isomer-specific systemic accumulation of zuclomiphene across consecutive cycles of treatment. The combined maximum concentration of enclomiphene and zuclomiphene attained in practice approximates 100 nmol/L and is generally well below levels previously demonstrated to have adverse effects in vitro.

Selection of ovarian stimulation protocol is related to IVF treatment outcome in women 35 years of age and older

PURPOSE

The aim of this study was to assess if the woman's age influenced IVF treatment outcome when a long GnRHa-hMG or a CC-hMG ovarian stimulation protocol was used. Two hundred women were included in the study, 100 women under the age of 35 and 100 women 35 years of age and older (mean 31.8 years and 36.7 years respectively). In the younger group as well as in the older group 50 women were stimulated according to a GnRHa-hMG protocol and 50 women received a CC-hMG regimen.

RESULTS

Significant differences between stimulation protocols were found in the older group for the mean numbers of oocytes recovered (4.7 vs 3.0), preembryos obtained (3.2 vs 2.0) and replaced (2.3 vs 1.7), as well as pregnancy (30% vs 10%) and delivery (24% vs 4%) rates per replacement.

CONCLUSION

It is concluded that women over 35 years of age seem to have a more favorable outcome of IVF treatment when using a long GnRHa-hMG protocol compared with CC-hMG, while this difference was not as obvious and lacking statistical significance under the age of 35.

The effect of clomiphene citrate isomers on human granulosa-lutein cells in culture

The effect of racemic clomiphene citrate and its two individual isomeric forms (i.e. en and zu) on corpus luteum function was evaluated. Granulosa-lutein cells were obtained from three normal ovulatory women undergoing oocyte retrieval following ovulation induction with agents other than clomiphene citrate for in vitro fertilization--embryo transfer (IVF-ET). The granulosa cells were cultured in the presence and absence of the three forms of clomiphene citrate, and in the presence and absence of human chorionic gonadotropin (hCG). Patients were recruited from the unit for assisted reproductive technology in a university hospital. The main outcome measured was the production of estradiol and progesterone by cultured human granulosa cells under the various conditions described above. The production of estradiol and progesterone by the cultured granulosa cells was dose-dependently reduced to a similar extent by all three forms of clomiphene citrate. The addition of hCG augmented steroidogenesis in all groups at all concentrations, but this still remained lower in all clomiphene citrate-treated groups compared to controls. The data suggest that all three types of clomiphene citrate (racemic, en, and zu) have inhibitory effects on the production of estradiol and progesterone by cultured human granulosa-lutein cells.

Gamete intrafallopian transfer: ethical considerations, historical development of the procedure, and comparison with other advanced reproductive technologies

OBJECTIVE

To report on ethical considerations regarding GIFT as well as the developmental history of the procedure and to review the literature and compare it with other advanced reproductive technologies (ARTs).

DESIGN

Indications, patient screening, recent evaluations, methods of ovarian hyperstimulation and oocyte retrieval-assessment, gamete transfer and pregnancy outcome are discussed in this review. A comparison of GIFT with other ARTs is also attempted.

MAIN OUTCOME MEASURES

Gamete intrafallopian transfer pregnancy determination and outcome.

CONCLUSIONS

Gamete intrafallopian transfer is an ethically acceptable procedure by different religious groups. In a selected group of patients, GIFT is an acceptable and, in some occasions, a preferable procedure to other ARTs.

Ovulation induction in polycystic ovary syndrome: a review of conservative and new treatment modalities

Polycystic ovary syndrome (PCOS) is a complex disorder with heterogeneous clinical and endocrine features. Chronic anovulation and infertility are common and affect about 75% of the patients. Ovulation induction in PCOS patients is a challenge for the physicians who treat these patients. Several different treatment modalities have been proposed to induce ovulation in PCOS, each of which deals with a different clinical or endocrine disorder which is present in these patients. This review presents traditional and new methods for ovulation induction in PCOS patients, the theoretical background, the pros and cons for each treatment and success rate.

Preovulatory administration of clomiphene citrate to mice causes fetal growth retardation and neural tube defects (exencephaly) by an indirect maternal effect

Clomiphene citrate was administered to female mice at different doses and different times prior to ovulation, in the preimplantation period after ovulation, and after implantation. Pregnancy outcome was determined on day 15 of gestation, when the number of implantations and resorptions were calculated relative to the number of ovulations, and fetuses were assessed for size and stage of development and morphological abnormalities. Preovulatory administration of clomiphene citrate caused decreased implantation rates and growth retardation of surviving fetuses, the degree of the effect being dependent on the dose and the time of drug injection relative to ovulation. The implantation rate was lowest, and the degree of fetal growth retardation highest, when clomiphene citrate was administered immediately before ovulation. An increased incidence of exencephaly was found in the fetuses of females injected with clomiphene citrate prior to ovulation. Transfer of blastocysts from treated mice to untreated fosters showed the effect of clomiphene citrate on implantation and fetal growth to be predominantly mediated through the female reproductive tract, rather than a direct effect on the embryo itself. Administration of clomiphene citrate in the preimplantational period resulted in complete inhibition of implantation, while the only effect when administration was after implantation was a slight reduction in fetal weight. These results indicate that preovulatory clomiphene citrate impairs uterine function, which has an indirect effect on the growth and development of the postimplantation embryo.

Interleukin-1: local production and modulation of human granulosa luteal cells steroidogenesis

OBJECTIVES

To investigate the possibility of local interleukin-1 (IL-1) and IL-1 inhibitor production by human granulosa and cumulus cells and to assess their direct effects on the steroidogenesis of these cells in vitro.

DESIGN

Prospective study.

PARTICIPANTS

Normal ovulatory women undergoing ovulation induction for in vitro fertilization.

INTERVENTION

Pretreatment of patients with gonadotropin-releasing hormone analogue, human menopausal gonadotropin, and human chorionic gonadotropin (hCG).

MAIN OUTCOME MEASURES

Retrieval and isolation of granulosa luteal cells and follicular fluid (FF). Granulosa luteal cells and cumulus cells cultured and analyzed by fluorescent activated cell sorter. Follicular fluid separated and bioassayed for IL-1 and IL-1 inhibitory activity. Steroid measurement performed. Interleukin-1 inhibitor purified. Interleukin-1 and IL-1 inhibitor bioassay performed. Statistical analysis made and interpreted.

RESULTS

Interleukin-1, but not IL-1 specific inhibitory activity, was found in granulosa and cumulus cell cultures and also in FF, only after its purification on a high-pressure liquid chromatography column. Under nonstimulated conditions, neither IL-1 nor IL-1 inhibitor had any effect on basal progesterone (P) or estradiol (E2) secretion. However, IL-1 inhibitor demonstrated significant (P < 0.01) inhibition of hCG-stimulated P secretion (from 200 to 110 ng/10,000 cells per 24 hours). In addition, IL-1 demonstrated a significant (P < 0.05) and dose-dependent inhibition of hCG-stimulated E2 production (from 6,832 +/- 460 to 4,237 +/- 141 pg/10,000 cells per 24 hours).

CONCLUSIONS

Interleukin-1 may exert a significant local autocrine regulatory role in the human ovary.

The effect of ethinyl estradiol on endometrial thickness and uterine volume during ovulation induction by clomiphene citrate

OBJECTIVE

To assess the deleterious effect of clomiphene citrate (CC) on the development of the endometrium and its improvement by the addition of ethinyl estradiol (E2). PARTICIPATING PATIENTS: Infertility-treated patients, monitored for induction of ovulation or timing of insemination (control group).

DESIGN

We studied four groups of women during an ovulatory cycle with various treatment schedules. Group 1: untreated patients; group 2: patients treated by CC; group 3: patients treated by CC + ethinyl E2; group 4: patients treated by human menopausal gonadotropin. Follow-up of the patients was done by vaginal ultrasonography and measurements of blood E2.

RESULTS

In the group treated by CC, both endometrial thickness and uterine volume growth during the follicular phase were lower as compared with untreated controls and menotropin-treated patients. The addition of ethinyl E2 to these patients reversed this deleterious effect of CC without interfering with ovulation.

CONCLUSION

Ethinyl E2 may reverse the deleterious effect of CC on endometrial development during the follicular phase.

Effects of clomiphene citrate and leuprolide acetate on luteal-phase hyperprolactinemia during ovarian stimulation with menopausal gonadotropins

Hyperprolactinemia, a known modulator of reproductive function, occurs commonly in women undergoing ovarian stimulation with human menopausal gonadotropins (hMG). Clomiphene citrate (CC) and gonadotropin releasing hormone analogues (GnRHa), when administered during the luteal phase, attenuate the hyperprolactinemic response to hMG. We asked whether follicular-phase administration of CC and GnRHa, as employed clinically in women undergoing ovarian stimulation for in vitro fertilization or gamete intrafallopian transfer, would alter the incidence and severity of hMG-induced luteal-phase hyperprolactinemia. Seventy-five percent of all patients had at least one luteal prolactin level greater than 25 ng/ml, and 40% had mean luteal-phase prolactin levels greater than 25 ng/ml. The incidence of hyperprolactinemia was similar in pregnant and nonpregnant cycles. The incidence of hyperprolactinemia was similar for both the GnRH agonist-treated group and those given clomiphene citrate. The increase in mean luteal prolactin levels over the follicular-phase baseline level was significantly greater in the CC-treated group (P = 0.03). This was due to the significant suppression of follicular-phase baseline prolactin levels in patients receiving CC. We conclude that neither CC nor GnRHa administration in the follicular phase prevents luteal-phase hyperprolactinemia in women undergoing ovarian stimulation with hMG.

Technique for cellular microsurgery using the 193-nm excimer laser

A new cell surgery technique has been developed to produce well-defined alterations in cells and tissue without detectable heating and/or other structural damage in the surroundings. The technique involves the use of an argon fluoride excimer laser, in the deep ultraviolet (UV) region of the spectrum at 193 nm, which is guided through a glass pipette filled with a positive air pressure. To demonstrate the method, holes were drilled in the zona pellucida of mouse oocytes. The diameter of the drilled hole was determined by the pipette tip size, and its depth by an energy emitted per pulse and number of pulses. Scanning electron microscopy of the drilled mouse oocytes showed uniform, round, well-circumscribed holes with sharp edges. Oocytes that had their zona pellucida drilled with this new method fertilized in vitro and developed to the blastocyst stage in a rate similar to that of control group. These results demonstrate the nonperturbing nature of this cold laser microsurgical procedure. In addition to the extension of our results for clinical in vitro fertilization purposes, such as enhancement of fertilization and embryo biopsy, there are wide-ranging possible uses of our method in fundamental and applied investigations that require submicron accuracy in cellular alteration.

Gonadotropin-releasing hormone antagonists attenuate estrogen/progesterone-induced hyperprolactinemia in monkeys

Previous studies have documented that exogenous gonadotropin-releasing hormone (GnRH) stimulates prolactin (PRL) secretion and augments thyrotropin-releasing hormone-induced PRL release. Further, the concomitant pulsatile release of PRL and luteinizing hormone (LH) suggests that GnRH may be an important regulator of PRL release in certain physiologic states. The authors explored this possibility by evaluating the effect of a GnRH antagonist ([Ac-pClPhe1, pClPhe2, DTrp3, DAla10]-GnRH; GnRH-antagonist) on PRL secretion in monkeys with induced hyperprolactinemia. Monkeys were given estradiol (E2) benzoate 25 mg/kg intramuscularly (IM) on cycle days 1 to 28, and a 3-cm progesterone (P) silastic capsule was placed on cycle day 15 and removed on day 28. On cycle days 15 to 28, monkeys were given IM injections of 1 mg/kg GnRH-antagonist (n = 3), 2 mg/kg GnRH-antagonist (n = 3), or vehicle (n = 3). Daily blood samples were assayed for E2, P, and PRL. The degree of PRL elevation was calculated as percent increase in area under the curve for days 15 to 28 when compared with days 1 through 14 (baseline). Luteinizing hormone levels were calculated similarly. Results indicate a dose-dependent effect of GnRH-antagonist on PRL secretion, with the larger dose producing a significantly lower hyperprolactinemic response, as well as a decline in LH. Thus, GnRH-antagonist attenuates induced hyperprolactinemia in a dose similar to that which suppresses LH release. These findings suggest that GnRH is a physiologic regulator of pituitary PRL secretion. In addition, GnRH analogs may be of benefit in controlled ovarian hyperstimulation by attenuating gonadotropin-induced hyperprolactinemia, thereby reducing potential adverse effects on fertility.

The effect of clomiphene citrate on human preovulatory oocyte maturation in vivo

Sixty-four infertile women underwent diagnostic laparoscopy in the periovulatory period at time-bracketed intervals following their endogenous luteinizing hormone (LH) surge. Forty-eight of these women were studied during natural cycles and 16 had mild oligoovulation and were administered clomiphene citrate (CC) to regulate their cycles. No patient received human chorionic gonadotropin. No patient was undergoing either in vitro fertilization (IVF) or gamete intrafallopian transfer (GIFT). Follicle puncture was performed and the oocytes were observed immediately for stage of maturation. Oocytes obtained from follicles exposed to CC were found to require an increased interval of time to reach metaphase I compared to oocytes obtained from natural cycles (27.75 +/- 2.2 vs 22.5 hr; mean +/- SE). Furthermore, the interval of time required for metaphase I oocytes to achieve metaphase II was statistically significantly shortened for CC cycles (2.4 hr for CC vs 10 hr for natural cycles. Nevertheless, there was no difference between natural and CC cycles in the time interval between LH surge onset and ovulation. These in vivo findings suggest a direct effect of CC on human oocyte maturation and may help explain the well-established discrepancy between the relatively high ovulation rate and the relatively low conception rate in clomiphene-induced cycles.

Future directions: anti-hormones in reproductive medicine

Anti-hormones are important in reproductive medicine because they are useful tools that teach us about the normal physiological actions of hormones. They also provide effective therapies to control or treat a variety of pathogenic processes. We expect that the future repertoire of anti-hormones will include the paracrine and autocrine regulators of specific cell functions, in addition to the endocrine systems described here. The availability of recombinant DNA expression systems for an ever larger portion of the human genome will surely accelerate the development of novel anti-hormones.

Effect of clomiphene citrate on in vitro ovulated ova

The effect of clomiphene citrate (CC) on developmental capacity of ovulated ova was studied with isolated in vitro perfused rabbit ovaries. Fifty-two ovulated ova were recovered from ovaries perfused with human chorionic gonadotropin (hCG) in a medium containing CC and 45 ova from ovaries perfused with hCG in a CC-free medium. Ova were cultured and inseminated with capacitated sperm and observed serially for evidence of fertilization and stage of development. CC did not affect the fertilization of ovulated ova. However, the percentage of ova which had reached the morula stage by 60 hours was significantly reduced in the CC-treated (15.4%) group, compared with the control group of ovaries (48.9%). A significant percentage of inseminated ova from CC-treated ovaries (65.4%) showed evidence of degeneration, as compared with control ovaries (37.8%). Thus, a partial loss of developmental capacity may explain the discrepancy observed between the rate of successful ovulation induction and the establishment of pregnancy associated with CC administration in humans.

The effects of enclomiphene and zuclomiphene citrates on mouse embryos fertilized in vitro and in vivo

The ovulatory agent clomiphene citrate, a racemic mixture of the estrogenic zuclomiphene and antiestrogenic enclomiphene isomers, has been associated with gamete/embryo toxicity in various animal models. To assess the potential effects of these isomers on fertilization and early embryogenesis, 3200 embryos were obtained from mouse oocytes fertilized in vivo and in vitro and exposed to increasing concentrations of zuclomiphene, enclomiphene, and clomiphene citrate in culture. Fertilization rates (p less than 0.01), blastocyst formation rates (p less than 0.02), and degeneration rates (p less than 0.005) were all adversely affected in a dose-dependent fashion. There were no statistically significant differences between the two isomers. Preincubation with 17 beta-estradiol did decrease the degenerative changes induced by clomiphene citrate but did not improve the decreased rate of blastocyst formation. These findings suggest adverse effects of a high concentration of clomiphene citrate and its isomers on fertilization and early mouse embryo growth that may have implications in the clinical use of this drug.

Antiestrogenic effect of clomiphene citrate in a multiple follicular stimulation protocol

End-organ antiestrogenic effects of clomiphene citrate (CC) have been demonstrated in the female reproductive tract at the levels of the ovary, cervix, and endometrium. However, it has not been established whether this effect is manifested during concomitant human menopausal gonadotropin (hMG) administration, as occurs in hMG/CC stimulations of multiple follicular development. To assess this question a review was made of serum estradiol (E2) and cervical mucus in 47 hMG and 56 hMG/CC stimulations on days -2, -1, 0, and +1 relative to the day of hCG administration. E2 levels (pg/ml) were significantly lower in the hMG as compared to the hMG/CC group. However, comparing the hMG and hMG/CC groups, cervical mucus scores were significantly higher in the former. Furthermore, an analysis of covariance demonstrated that the cervical mucus scores on each day were significantly lower in the hMG/CC group (P less than 0.001). Thus, in hMG/CC stimulations for in vitro fertilization (IVF), despite the concomitant administration of pharmacologic doses of hMG, CC exerts an antiestrogenic effect on at least one end organ, cervical mucus production. Potentially, this antiestrogenic effect in IVF stimulations would be exerted at other female reproductive tract sites including the endometrium; however, its clinical significance, if any, is unclear.

A comparison of fixed regimens for obtaining human cleaving oocytes for research purposes

A fixed schedule for ovarian stimulation and follicular aspiration, previously used in our department for research purposes, was modified in an attempt to increase the recovery and cleavage rates of the oocytes. Three different clomiphene regimens were used to stimulate the ovaries of normal volunteer women requesting laparoscopic sterilization (50 mg and 150 mg daily for 5 days, and 50 mg daily for 10 days). Oocytes were recovered from 83% of the aspirated follicles, i.e. 1.6 oocytes/patient: 65% of the oocytes cleaved after in-vitro fertilization and, on average, 1.0 cleaving egg was obtained per patient. There were no differences in the recovery and cleavage rates between the three clomiphene regimens. It is concluded that a sufficient number of cleaving embryos for research purposes can be generated with the present fixed regimen, which offers little inconvenience to the volunteers as the day of egg recovery can be predicted some time in advance.

Follicular development: lessons learned from human in vitro fertilization

In vitro fertilization has offered new insights into our understanding of ovulation induction, folliculogenesis, and luteal phase events. This new information is provided by the ability to precisely study these cycles in a frequent and sequential fashion through the use of peripheral blood markers, ultrasound evaluation, and follicular fluid constituents and cell culture techniques, as well as direct observation of the oocyte, fertilization, and cleavage. In these stimulated cycles the follicular phase serum estradiol levels in conjunction with ultrasound were evaluated; a poor correlation was shown between follicle size and number and estrogen production. This distinct dyssynchrony suggests the recruitment of a number of cohorts of follicles in each stimulated cycle. From the biochemical markers in follicular fluid, cyclic adenosine monophosphate has a distinct predictive value in regard to pregnancy in in vitro fertilization-embryo transfer cycles. In the luteal phase, the mass effect of aspiration of great numbers of granulosa cells, the effect of supplemental progesterone, and the influence of high follicular phase estradiol levels remain controversial and, therefore, a less clear cut pattern emerges. Variations in the protocol have not greatly improved the major problems of folliculogenesis associated with ovulation induction and an in vitro fertilization-embryo transfer program, that is, follicular asynchrony and luteal phase deficiency.

Embryo toxicity of clomiphene citrate on mouse embryos fertilized in vitro and in vivo

The effect of the ovulatory agent clomiphene citrate on fertilization and early embryogenesis was investigated with the use of in vitro fertilized mouse oocytes. Alterations in early embryogenesis with clomiphene citrate exposure were further studied with the use of embryos obtained from mouse oocytes fertilized in vivo. In the nontreated group, the fertilization rate was 81%, and 61% of the oocytes reached the blastocyst stage by 96 hours. Both fertilization and blastocyst formation declined in a dose-dependent fashion when clomiphene citrate was added to the culture media in concentrations greater than or equal to 10 micrograms/ml (p less than 0.001). The rate of progressive embryo cleavage was also slower at 48 and 72 hours after drug exposure. Mouse embryos fertilized in vivo demonstrated similar findings, with decreased blastocyst formation and increased degeneration rates, again at clomiphene citrate concentrations greater than or equal to 10 micrograms/ml (p less than 0.01). Exposure to the drug beyond 24 hours had no additional effect. It appears that clomiphene citrate-exposed embryos may undergo subtle changes that later manifest themselves in the form of decreased embryo growth rates and increased embryo degeneration rates.

The day of initiation of human menopausal gonadotropin stimulation affects follicular growth in in vitro fertilization cycles

The attainment of synchronous follicular development in human menopausal gonadotropin/human chorionic gonadotropin-stimulated cycles for in vitro fertilization (IVF) continues to be a perplexing problem. Two regimens of follicle stimulation for IVF cycles were, therefore, compared. Twenty-nine patients commenced human menopausal gonadotropin (hMG) therapy on day 1 of the menstrual cycle (Group I), while 30 women received hMG from the third day of the cycle (Group II). The hMG therapy was tailored to the individual patients's response, based on ultrasonographic measurements of follicular size and serum estradiol (E2) levels. Both groups of patients received a mean of 19.6 +/- 1.4 ampules of hMG over a mean of 6.1 +/- 0.2 days. The pattern of serum E2 and progesterone levels in the periovulatory and luteal phase was not affected by the day of initiation of hMG therapy, although Group I patients demonstrated lower (P less than 0.05) E2 levels on the 2 days prior to human chorionic gonadotropin (hCG) administration. In terms of follicle growth, Group II follicles consistently demonstrated a significantly (P less than 0.01, chi 2 test) larger proportion of medium- and large-sized follicles compared to Group I follicles on almost all of the days when ultrasonographic measurements were taken. In addition, Group II follicles demonstrated an earlier shift (day-1) to the larger follicles than Group I follicles (day 0). Significantly (P less than 0.001) more oocytes were recovered per aspirated follicle in Group II patients, but the fertilization rate per oocyte was greater (P less than 0.003) for Group I oocytes. Nevertheless, pregnancy rates did not differ between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Direct ovarian effect of clomiphene citrate in the rabbit

The effects of clomiphene citrate (CC) on ovulation and ovum maturation were studied using the isolated perfused rabbit ovary. CC (10(-5) M) added to the perfusate with human chorionic gonadotropin (50 IU) did not affect ovulatory efficiency, ovulation time, oocyte maturation, or degeneration of ovulated ova and follicular oocytes. During perfusion without human chorionic gonadotropin, the percentage of follicular oocytes with germinal vesicle breakdown was significantly increased in response to CC (10(-5) M or 10(-7) M); a greater percentage of follicular oocytes was degenerated. Estradiol (100 ng/ml) added to the perfusate reversed the effect of CC on degeneration of follicular oocytes. Of follicular oocytes from ovaries perfused with CC, 79.3% were degenerated; in contrast, 25% were degenerated in ovaries treated with CC plus estradiol. These data suggest that CC has a direct ovarian effect and that ovum degeneration associated with CC may be related to an antiestrogenic action.

Effect of clomiphene citrate on the rabbit ovary

The effect of clomiphene citrate on the rabbit ovary was studied in mature nulliparous rabbits pretreated with three consecutive doses ranging from 0.01-10.0 mg/kg per day. With increasing doses a trend of decrease in mean ovarian weight (mg/kg body weight) is observed 2 days after termination of treatment. Five days later a significant increase occurs, which then subsides again to control values on day 12 after termination of treatment. During this period, no matings or injections of luteinizing hormone were performed to trigger ovulation; consequently no ovulations are observed. Folliculogenesis appears as normally; number and morphology of follicles are within normal ranges. No endogenous, spontaneous gonadotropin surges are detected in blood serum up to the 7th day after termination of treatment (2 and 10 mg doses). The surface epithelium of the ovary resembles normal germinal epithelium; however, after treatment with high doses a "secretory"-like activity is observed, accompanied with ultrastructural changes.

Altered follicular development in clomiphene citrate versus human menopausal gonadotropin-stimulated cycles for in vitro fertilization

The pattern of periovulatory and luteal phase serum estradiol (E2) and progesterone (P) as well as follicular fluid (FF) E2, P, androgen, gonadotropin, and prolactin concentrations of eight women undergoing clomiphene citrate (CC)/human chorionic gonadotropin (hCG) stimulation and eight women undergoing human menopausal gonadotropin (hMG)/hCG stimulation of follicular development for the purpose of in vitro fertilization were compared. Ovulation was induced with either a 5-day course of CC (100 mg/day beginning on day 5 of the cycle) or an individualized hMG regimen, and laparoscopy was performed 36 hours after hCG administration. The length of the luteal phase was significantly longer (P less than 0.05) in the CC-treated group as compared with the hMG-treated group. The pattern of serum E2 levels differed significantly (P less than 0.01) in that E2 levels were lower in the early and midluteal phase in CC-stimulated cycles; in addition, a delayed second E2 peak was observed in the late luteal phase in these women. Serum P levels, however, were lower in the hMG-stimulated group. Analysis of FF hormone concentrations revealed significantly (P less than 0.05) higher concentrations of E2 and androsterone in the FF of hMG-treated patients. It is concluded that follicular development in CC-stimulated cycles differs markedly from that in hMG-stimulated cycles. These differences may reflect either an altered follicular maturational process or may represent a direct inhibitory effect of CC on follicular steroidogenesis.