The use of progesterone antagonists and progesterone receptor modulators in contraception

Progesterone antagonists (PAs) and progesterone receptor modulators (PRMs) have contraceptive potential by suppressing follicular development, delaying the surge of luteinizing hormone (LH), retarding endometrial maturation, and promoting endometrial bleeding. Mifepristone, in daily doses of 2-10 mg, blocks the LH surge and ovulation. Many of the studies were conducted in women not at risk of pregnancy, and thus the contraceptive efficacy is not yet known. Nevertheless, there is evidence that daily doses of 2 or 5 mg of mifepristone have contraceptive potential. Because of anovulation, there may be an unopposed estrogen effect on the endometrium, although this risk may be mitigated by the noncompetitive anti-estrogenic activity exhibited by both PAs and PRMs. Low doses of PAs and PRMs, which do not affect ovulation, retard endometrial maturation, indicating that the endometrium is exquisitely sensitive to these compounds. This raises the prospect of endometrial contraception, i.e. prevention of endometrial maturation without disturbing ovulation or producing alterations in bleeding patterns. This approach works well in monkeys but was not found to be very promising when given to women not using contraception. On the other hand, 200 mg mifepristone administered 48 h after the LH surge, which has minimal or no effect on ovulation and bleeding patterns, is an effective contraceptive; yet, it is not a practical approach to contraception. Late luteal phase administration of mifepristone produces menstrual bleeding. However, when mifepristone was administered every month at the end of the cycle either alone or together with prostaglandins, it was not very effective in preventing pregnancy. In contrast, a mifepristone-prostaglandin combination has been shown to be a very effective treatment for occasional menstrual regulation, with vaginal bleeding induced in 98% of pregnant women, with menses delay of 11 days or less. Mifepristone is an excellent agent for emergency contraception when used within 120 h of unprotected intercourse. It is also possible that PAs and PRMs may be used to reduce the occurrence of bleeding irregularities induced by progestin-only contraceptive methods. Both classes of progesterone receptor ligands may also have contraceptive efficacy by having a pharmacological effect on the embryo or altering tubal transport or other aspects of tubal physiology.

Interventions for emergency contraception

OBJECTIVES

To determine which emergency contraceptive method following unprotected intercourse is the most effective, safe and convenient for use in preventing pregnancy.

SEARCH STRATEGY

The search strategy included electronic searches of the Cochrane Controlled Trials Register, Popline, Chinese biomedical databases and HRP emergency contraception database. In addition, references of retrieved papers were searched and researchers in the field and two pharmaceutical companies were contacted.

SELECTION CRITERIA

Randomized or quasi-randomized studies including women attending services for emergency contraception following a single act of unprotected intercourse were eligible.

DATA COLLECTION AND ANALYSIS

Data on outcomes and trial characteristics were extracted in duplicate by two reviewers. Results were expressed as relative risk using a fixed-effects model with 95 % confidence interval.

MAIN RESULTS

Fifteen trials were included in the review. The majority (8/15) of the trials were conducted in China. Most comparisons between different interventions included one or two trials although some trials were appropriately sized with power calculations. Levonorgestrel appears to be more effective than Yuzpe regimen (2 trials, RR: 0.51, 95 % CI: 0.31-0.84) and causes less side-effects (RR: 0.80, 95 % CI: 0.76 to 0.84). Levonorgestrel was less effective than locally manufactured mifepristone in a single, large Chinese study (RR: 2.17, 95 % CI: 1.00 to 4.77). Effectiveness of different doses of mifepristone seem to be similar but the frequency of delay in onset of the subsequent menstrual period increases with increased dose.

REVIEWER'S CONCLUSIONS

Levonorgestrel and mifepristone seem to offer the highest efficacy with an acceptable side-effect profile. One disadvantage of mifepristone is that it causes delays in onset of subsequent menses which may induce anxiety. However, this seems to be dose-related and low doses of mifepristone minimise this side-effect without compromising effectiveness. Future studies should compare the effectiveness of mifepristone with levonorgestrel.

Multicenter study of the Lactational Amenorrhea Method (LAM): I. Efficacy, duration, and implications for clinical application

A multicenter study of the Lactational Amenorrhea Method (LAM) was carried out to test the acceptability and efficacy of the method. Additionally, the data are used to test new constructs for improvement of method criteria. A protocol was designed at the Institute for Reproductive Health (IRH), Department of Obstetrics and Gynecology, Georgetown University Medical Center, a World Health Organization (WHO) Collaborating Center, and was reviewed and modified in collaboration with the co-sponsors, the World Health Organization and the South to South Cooperation for Reproductive Health, and the principal investigators from each site. Data were gathered prospectively on LAM acceptors at 11 sites. Data were entered and cleaned on-site and further cleaned and analyzed at IRH, using country-level and pooled data to produce descriptive statistics and life tables. The 98+% efficacy of LAM is confirmed in a wide variety of settings. In addition, the results yield insight on the possibility of continued use beyond 6 months. LAM is found to be highly effective as an introductory postpartum method when offered in a variety of cultures, health care settings, socio-economic strata, and industrial and developing country locales. In addition, LAM acceptance complements breastfeeding behaviors without ongoing breastfeeding support services. The parameters studied yield high efficacy and method continuation. Therefore, the basic tenets of the 1995 Bellagio consensus on LAM is reconfirmed and it is recommended that LAM be reconfirmed and it is recommended that LAM be incorporated into hospital, maternity, family planning, maternal and child health, and other primary health care settings.

Multicenter study of the Lactational Amenorrhea Method (LAM): II. Acceptability, utility, and policy implications

A multicenter study of the Lactational Amenorrhea Method (LAM) was carried out to determine acceptability, satisfaction, and utilization in 10 different populations, and to confirm the efficacy of the method. Efficacy data are presented in a companion paper. A protocol was designed at the Institute for Reproductive Health (IRH), Department of Obstetrics and Gynecology, Georgetown University Medical Center, and reviewed and modified in collaboration with the co-sponsors, the World Health Organization, the South-to-South Cooperation for Reproductive Health, and the principal investigators from each site. Data were gathered prospectively on LAM users at 11 sites. Data were entered and cleaned on-site, and further cleaned and analyzed at IRH, using country-level and pooled data to produce descriptive statistics. The overall satisfaction with LAM was 83.6%, and continuation with another method of family planning was shown to be 67.6% at 9 months postpartum, in most cases exceeding previous use of contraception prior to use of LAM. Knowledge and understanding of the method at discontinuation were high, ranging from 78.4 to 88.6% for the three criteria. LAM can be used with a high level of satisfaction and success by women in a variety of cultures, health care settings, socio-economic strata, and industrial and developing country settings. The results confirm that LAM is acceptable and ready for widespread use, and should be included in the range of services available in maternal and child health, family planning, and other primary health care settings.

Effects of two antiprogestins on early pregnancy in the long-tailed macaque (Macaca fascicularis)

The abortifacient effects of mifepristone and HRP 2000 were compared in gravid long-tailed macaques. Thirty-six animals were studied with treatment administered either by the oral (0.5 or 5.0 mg/kg; N = 5 per antiprogestin per dose) or intramuscular (i.m.) routes (0.5 mg/kg; N = 5 per antiprogestin) on gestational days (GD) 23-26; six vehicle controls were included. Blood samples were collected for assay of progesterone (P4) and each of the antiprogestins (pre-treatment, daily GD 23-28, every other day GD 30-40), and animals were monitored sonographically throughout gestation. Results of these studies indicated high rates of abortion with i.m. administration (3/5 mifepristone, 4/5 HRP 2000) and 5.0 mg/kg oral route (4/5, 2/5, respectively), with less effects noted at oral doses of 0.5 mg/kg (2/5, 0/5, respectively). No early abortions were observed in the control groups. Following daily i.m. treatment, peak levels of 8-16 ng/ml mifepristone were detected whereas 6-10 ng/ ml of HRP 2000 were noted (GD 26-27). No serum levels of mifepristone were detected following either of the oral doses whereas serum levels of 2-6 ng/ml HRP 2000 were noted with high dose oral administratation. Results of these studies suggest: (1) both antiprogestins are roughly comparable in terminating early pregnancy although HRP 2000 may be more efficacious when administered i.m. whereas mifepristone may be more effective when administered orally; (2) similar levels of biological activity are seen with the i.m. and high dose oral dosing regimens, with little or no activity with the oral low dose; and (3) infants resulting from surviving pregnancies were not affected by early gestation exposure.

Clinical uses of antiprogestogens

Antiprogestogens, which block the action of progesterone at the cellular level through binding to the progesterone receptor, are proving to be one of the most significant developments in endocrinology in recent years. Several hundreds of such compounds have been synthesized, but only a few of them have been evaluated to any significant extent in biological screening models and, to our knowledge, only three compounds, namely mifepristone, lilopristone (ZK 98.734) and onapristone (ZK 98.299) have been given to humans. Most of the clinical research to date has focused on the use of mifepristone given in combination with prostaglandin for termination of early pregnancy, an indication for which the compound is being used routinely in four countries so far, i.e. China, France, the UK and Sweden. The gynaecological and obstetrical applications in which antiprogestogens have been shown to be of value to date include ripening of the pregnant cervix prior to pregnancy termination, sensitization of the uterus to prostaglandins in second-trimester abortion, and induction of labour. Available data suggest that antiprogestogens have no place in the conservative treatment of ectopic pregnancy or in the treatment of premenstrual tension. In fertility regulation, the sequential combination regimen of mifepristone plus prostaglandin as used for inducing abortion has proved to be effective also for menses induction and can be expected to be an efficacious once-a-month contraceptive. Mifepristone alone, without adjuvant prostaglandin, has yielded promising results as an anti-implantation agent and in emergency contraception. Other potential uses include once-a-week contraception, ovulation inhibition (in a sequential regimen with a progestogen), and as a daily mini-pill. Mifepristone, and other antiprogestogens for which biological data have been reported also bind to the cellular receptors for glucocorticoid hormones and, consequently, possess antiglucocorticoid in addition to their antiprogestational activity. Because of this antiglucocorticoid effect, mifepristone has been employed successfully in the palliative treatment of hypercortisolism due to Cushing's syndrome, and its use has been proposed for treating certain forms of depression and of glaucoma, and in wound healing. However, for scientific and practical reasons, it would be preferable if molecules were developed that have only the antiprogestational or the antiglucocorticoid activity rather than both.

Pharmacokinetic study of RU 486 and its metabolites after oral administration of single doses to pregnant and non-pregnant women

RU 486 and three of its metabolites (RU 42633-monodemethyl, RU 42848-didemethyl, and RU 42698-hydroxymetabolite) were determined by HPLC in plasma from nine non-pregnant and 36 pregnant women. Each non-pregnant subject took an oral dose of RU 486 (25, 100, 400 and 600 mg consecutively) once per menstrual cycle. Six of the nine women also received a dose of 200 mg. The 36 pregnant women were randomized into four groups which were given a single dose of 25, 100, 400 or 600 mg RU 486. Blood samples were taken up to 120 h after dosing. Peak concentrations of RU 486 occurred on most occasions within 2 h. Plasma concentrations at 1 h and at 24 h increased in proportion to log dose. There was a wide variability (up to ten-fold) in the pharmacokinetic parameters within each dose group. Plasma concentrations of RU 42633 were similar to those of RU 486 but concentrations of RU 42848 and RU 42698 were much lower. As with RU 486, the plasma concentrations of the metabolites were maintained at high levels for up to 48-72 h after dosing. The findings were consistent with a rapid metabolism of RU 486 to RU 42633; removal of the second methyl group leading to RU 42698 occurred much more slowly and to a much less extent than removal of the first. There appeared to be no significant differences between the non-pregnant and pregnant women in either the plasma concentrations or pharmacokinetic parameters of RU 486 and its metabolites.

Tamoxifen as an antifertility agent in the long-tailed macaque (Macaca fascicularis)

The potential use of tamoxifen, a nonsteroidal antiestrogen, as an antifertility agent was studied in the long-tailed macaque (Macaca fascicularis). Twenty-six cycling females were bred, then treated with a single oral dose of tamoxifen (5 mg/kg) (N = 13) or vehicle (N = 13) on day 4 post-ovulation. Serum progesterone (P4) and tamoxifen concentrations were evaluated on post-ovulation days 4, 8, 12, 16, and 18. No effects of treatment were observed on P4 concentrations or on the fertility rate--pregnancy was achieved in 4/13 controls (31%) and 6/13 treated females (46%). Analysis for serum tamoxifen concentrations in samples collected during the fertility and a supplemental pharmacokinetic study (N = 3; single oral dose of 10 mg/kg; urine and serum evaluated) failed to reveal any detectable tamoxifen levels. It was concluded that (1) absorption of tamoxifen may be negligible under the described treatment regimens or (2) tamoxifen metabolism/clearance occurs at a rapid rate.

Emergency contraception

The term 'emergency contraception', as employed in this paper, refers to methods that are used as emergency procedures to prevent pregnancy following unprotected intercourse. Alternative, less appropriate, terms are postcoital and 'morning-after' contraception. References to postcoital preparations can be found as far back as 1500 BC in Egyptian papyri, but it was not until fairly recently that contraceptive research has been able to at least partially fulfill that need. The development of hormonal methods of emergency contraception goes back to the 1960s when the first human trials of postcoitally administered high-dose oestrogens were undertaken. Combined oestrogen- progestogen combination therapy (the so-called Yuzpe regimen) was introduced in the early 1970s, while the postcoital insertion of an intrauterine contraceptive device (IUD) for emergency contraception was first reported in 1976. Other compounds that have been tested more recently include levonorgestrel, the antiprogestogen mifepristone, and danazol. Although there is some debate about the magnitude of the protective effect, few people question the important role that emergency contraception can play in preventing unwanted pregnancy and hence maternal mortality and morbidity resulting from unsafe abortion. Given that the most often used methods of emergency contraception, namely the Yuzpe regimen and postcoital insertion of an IUD, rely on technology that has been available for some 30 years, family planning programmes that claim to be concerned with improving women's reproductive health, cannot really be excused if they do not provide emergency contraception as part of their routine services.

A multicenter clinical study on two types of levonorgestrel tablets administered for postcoital contraception

Contraceptive efficacy, cycle control and side effects of two types of 0.75 mg levonorgestrel tablets taken postcoitally during the periovulatory period of one cycle were studied in a multicenter trial involving 361 women. No significant differences were found between the two types of levonorgestrel pills in terms of contraceptive efficacy, cycle control and side effects. The failure rate observed (1.4% per treated cycle) was similar to that reported for other hormonal approaches to emergency postcoital contraception. Intermenstrual bleeding or spotting occurred in 11.5% of the cycles and anovulation as assessed from BBT charts in 14.4% of cycles. One or more side effects were reported by 22.2% of subjects. The relatively frequent occurrence of cycle disturbances and subjective side effects make it unlikely that the repeated postcoital use of levonorgestrel would be an acceptable routine method of contraception for most women.

Comparative cross-over pharmacokinetic study on two types of postcoital contraceptive tablets containing levonorgestrel

A pharmaceutical and pharmacokinetic study was carried out on levonorgestrel tablets from two different sources (Hungarian- and Chinese-made). Both preparations contained 0.75 mg levonorgestrel and had been shown to have similar contraceptive efficacy and side effects when used for postcoital contraception. Absorption and bioavailability of the Hungarian-made tablets were greater as evidenced by higher serum concentrations of levonorgestrel, a greater area under the concentration-time curve during the first 24 hours, and a more marked suppressive effect on SHBG levels. These differences most probably reflect differences in their pharmaceutical formulation, in particular the extent of tablet dissolution and the degree of micronisation of levonorgestrel.

Pharmacokinetic study of orally administered RU 486 in non-pregnant women

A method based on HPLC was devised for the estimation of RU 486 in blood and utilised to study the pharmacokinetics of a single dose of 50 mg RU 486 administered orally to 12 women on day 7 of the cycle. The dose was rapidly absorbed with peak plasma concentration between 1 and 2 hours. Distribution was also rapid (mean t1/2 alpha: 1.4h), whereas elimination was slow (mean t1/2 beta: 28.3 h). RU 486 was still detectable in some women at 72 h after administration. The plasma concentrations fitted the equation for a two-compartment open model from which the pharmacokinetic parameters were calculated. The mean total plasma clearance was 3.0 l/h, and the comparison of our data with those published studies suggests that the pharmacokinetics of RU 486 in Chinese women are similar to those of other populations.

Termination of early human pregnancy with RU 486 (mifepristone) and the prostaglandin analogue sulprostone: a multi-centre, randomized comparison between two treatment regimens

A multi-centre, randomized trial was conducted to compare the efficacy and side-effects of two combination regimens of the antiprogestin RU 486 and the intramuscular PGE2 analogue sulprostone for termination of early pregnancy (amenorrhoea up to 49 days). Women in the 3-day group (n = 125) received 25 mg RU 486 twice daily for 3 days plus a single injection of 0.25 mg sulprostone in the morning of the third day of antiprogestin treatment. In the 4-day group (n = 126), RU 486 was given for 4 days and the sulprostone injection in the morning of the fourth day. Treatment outcome in the two groups was similar. Overall, 88.8% had a complete abortion, 6.8% an incomplete abortion and 2.4% were treatment failures; in the remaining 2% treatment outcome could not be determined. Only three of the six women with treatment failure still had detectable fetal heart activity when the pregnancy was terminated by vacuum aspiration two weeks after the start of treatment. Five of the 17 interventions for incomplete abortion were carried out as emergency procedures because of heavy bleeding; two of these five women were given a blood transfusion. The majority of the curettages (10/17) were performed in one centre. If the data from this centre and the women with undetermined treatment outcome were excluded, the rates for complete abortion, incomplete abortion and treatment failure in the remaining six centres were 93.6, 3.7 and 2.7%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

The use of prostaglandins and antiprogestins for pregnancy termination

Although vacuum aspiration could be regarded as a simple procedure, complications do occur and attempts have been made to develop non-surgical procedures for termination of pregnancy during the first 3-4 weeks following the first missed menstrual period. A variety of prostaglandin (PG) analogs have been developed which are equally effective as vacuum aspiration to induce abortion during early pregnancy. However, the widespread acceptance of PG treatment is limited by a relatively high incidence of gastrointestinal side effects and uterine pain. Treatment with presently available antiprogestins alone is not sufficiently effective to compete with vacuum aspiration. However, administration of these compounds induces uterine contractions and increases the sensitivity of the myometrium to prostaglandin. These effects allow the development of sequential treatment with RU 486 and a low dose of PG analogs administered intramuscularly or vaginally which is highly effective and is seemingly associated with a lower frequency of side effects than if PG analogs are used alone. It can be concluded that this medical abortion method has the capacity to compete with vacuum aspiration for termination of early pregnancy. Randomized studies comparing the two procedures are, however, needed to confirm this statement.

Effect of oral prostaglandin E2 on uterine contractility and outcome of treatment in women receiving RU 486 (mifepristone) for termination of early pregnancy

It has been shown that the antiprogestin RU 486 (mifepristone) increases the sensitivity of the early pregnant human uterus to the stimulatory action of synthetic prostaglandin E (PGE) analogues. To examine if RU 486 also increases uterine sensitivity to the naturally occurring PGE2 given orally, two investigative approaches were used in the present studies: (i) direct registration of uterine contractions before and after PGE2 administration in untreated and RU 486-treated early pregnant women; and (ii) a double-blind, randomized, controlled efficacy trial involving treatment of pregnant women (amenorrhoea of less than or equal to 49 days) with RU 486 (25 mg twice daily for 4 days) and PGE2 (1 mg once or twice) or placebo on the last day of RU 486 treatment. The results indicate that oral PGE2 at the doses employed had little or no stimulatory effect on uterine contractility and that it did not improve the rate of complete abortion achieved with RU 486 alone. Overall, 25 of 42 women (59%) had a complete abortion, 15 women (36%) did not abort and the remaining two had incomplete abortions. Women with complete abortions had significantly lower pretreatment levels of progesterone and a longer duration of induced bleeding than those who did not abort. Thus oral PGE2, when given in clinically acceptable doses, is not a suitable alternative to synthetic PGE analogues for use in combination with RU 486 for termination of early pregnancy.

Medical approaches to termination of early pregnancy

Termination of early pregnancy by vacuum aspiration is a well-established technique. The procedure is highly effective and has a low complication rate, particularly when performed during the first few weeks after missed menses. However, this parasurgical method requires skilled health care personnel, and attempts have therefore been made to find medical alternatives. Prostaglandins were the first agents to be used successfully for this purpose, but the high incidence of mainly gastrointestinal side-effects has limited their widespread use. More recently, attention has focused on antiprogestational steroids, i.e., compounds that prevent the action of progesterone either by inhibiting its biosynthesis or by preventing it from binding to the cellular receptors in target organs. Current experience indicates that these compounds, particularly when used in combination with a low dose of a synthetic prostaglandin analogue, have the potential to become a safe, effective, and acceptable medical method for the termination of early pregnancy.

Anti-progesterones for the interruption of pregnancy

Therapeutic abortion can be performed effectively and safely by vacuum aspiration of the uterus up to 12 weeks of amenorrhoea. Although the operative procedure could be regarded as simple, complications do occur and attempts have been made to develop non-surgical means of terminating pregnancy in the first 3-4 weeks following the first missed menstrual period. A variety of PG analogues have been developed which induce abortion in over 90% of women when given by vaginal pessary or intramuscular injections (see Bygdeman, 1984). In a large multicentre study (WHO, 1987) 0.5 mg sulprostone, administered three times with 3 h intervals, was recently found to be equally as effective as vacuum aspiration for termination of early pregnancy. The frequencies of complete abortion were 91 and 94%, respectively. However, the widespread acceptance of PG treatment is limited by a relatively high incidence of gastrointestinal side-effects and uterine pain. Treatment with antiprogesterones, both mifepristone and epostane, effectively induces abortion during early pregnancy, but the frequency of complete abortion is too low to be clinically acceptable. It remains to be demonstrated if other antiprogesterones such as ZK 98.734 and ZK 98.299, currently under development, may change this conclusion. Administration of mifepristone induces uterine contractions and increases the sensitivity of the myometrium to prostaglandins. These effects allowed the development of sequential treatment with a low dose of mifepristone and PG analogues administered vaginally or intramuscularly. The combined therapy has been shown to be highly effective (frequency of complete abortion between 95 and 100%) and is seemingly associated with a lower frequency of side-effects than if PG analogues are used alone. Whether this medical abortion method will be a realistic alternative to vacuum aspiration during the first 8 weeks of pregnancy depends on the outcome of further clinical trials, including randomized studies comparing the two procedures. It has been shown that mifepristone crosses the placenta (Frydman et al, 1985). An important factor which needs to be verified in future studies is therefore the possible embryotoxicity of this type of compound. The risk that pregnancy continues in spite of treatment can never be excluded.(ABSTRACT TRUNCATED AT 400 WORDS)

Postcoital contraception with levonorgestrel during the peri-ovulatory phase of the menstrual cycle. Task Force on Post-ovulatory Methods for Fertility Regulation

The contraceptive efficacy and side effects of postcoital levonorgestrel used repeatedly during the peri-ovulatory period of one cycle was examined in 259 women. All subjects were of proven fertility in their present union and had ovulatory cycles as assessed from pre-treatment BBT charts. The mean number of coital acts during the treatment cycle was 7.5 (SD:2.6) and the mean number of 0.75 mg levonorgestrel tablets taken during the peri-ovulatory period was 4.0 (SD:1.2). Two pregnancies, both considered to be method failures, occurred, giving a failure rate of 0.8% per treated cycle. Although the overall effect of levonorgestrel on menstrual cycle length was small and insignificant, menstrual cycle disturbances were not uncommon. Intermenstrual bleeding or spotting occurred in 8.5% of the treated cycles and 12.5% of the cycles were less than 20 or more than 35 days. Other side effects, mainly nausea, headache and dizziness, were reported by about 20% of the subjects but the apparent incidence of these complaints varied markedly between the nine participating centres from 0% to just over 50%. The data suggest that repeated postcoital use of levonorgestrel is probably not a viable approach to fertility regulation for the majority of women who have regular intercourse and wish to limit the number of their pregnancies.

Changes in the concentration of prostaglandins in preovulatory human follicles after administration of hCG

The concentrations of prostaglandins F-2 alpha, E, D-2 and 13,14-dihydro-15-keto PGE were measured in follicular fluid collected from women undergoing routine laparoscopy following induction of follicular development with clomiphene and hCG. Laparoscopy was performed before, or at 12, 24 or 36 h after administration of hCG. Prostaglandins were measured as the methyloxime derivative by radioimmunoassay. Peaks in PGE and PGF-2 alpha concentration occurred at 12 and 36 h with a significant nadir at 24 h, whereas PGD-2 production was very low at 36 h. The concentration of PGF-2 alpha rose significantly between 0 and 36 h and was greatest in follicles yielding oocytes, suggesting a possible role for this prostaglandin in the mechanism of follicle rupture.

Meiosis-inducing substances in human preovulatory follicular fluid related to time of follicle aspiration and to the potential of the oocyte to fertilize and cleave in vitro

Meiosis-inducing substance (MIS) and steroid and gonadotropic hormones were investigated in 41 preovulatory follicular fluids (FFs) aspirated at either 0, 12, or 36 hours after human chorionic gonadotropin (hCG) administration in 25 women with clomiphene citrate-stimulated cycles. Twenty-one oocytes were recovered from these FFs and subjected to in vitro fertilization. MIS activity was present in 25 (61%) of the FFs. The frequency of MIS-active FFs increased from 11% (1 of 9) at 0 hours and 40% (2 of 5) at 12 hours to 81% (22 of 27) at 36 hours after hCG administration (P less than 0.001). The concentration of hormones in MIS-active FFs was not significantly different from that of MIS-inactive FFs. Twelve (86%) of 14 oocytes that fertilized and cleaved in vitro were recovered from MIS-active FFs. By contrast, all seven oocytes that remained unfertilized in vitro were recovered from MIS-inactive FFs. These findings support the notion that resumption of meiosis in the preovulatory oocyte is triggered by MIS in FF and suggest that follicular MIS production may be one of the factors that determines the success of in vitro fertilization and early embryonic development.

Effect of ampicillin or amoxycillin administration on plasma and urinary estrogen levels during normal pregnancy

Urinary estrogen excretion and plasma levels of conjugated and unconjugated 17 beta-estradiol and estriol were measured in 10 healthy, pregnant women before, during and after a 5-day course of orally administered ampicillin (2 g/day) or the same dose of amoxycillin. On the second and third day of ampicillin treatment the plasma level of conjugated estriol and the urinary estrogen level were lower than pretreatment values, but then returned to basal values despite continuing treatment. Plasma concentrations of conjugated and unconjugated 17 beta-estradiol and of unconjugated estriol did not show any significant change during treatment. Hormone changes in women on amoxycillin were qualitatively similar to but smaller and less consistent than those induced by ampicillin. The results indicate (1) that the use of amoxycillin instead of ampicillin in pregnancies that require estrogen monitoring of feto-placental function, has little clinical advantage, and (2) that the adverse effect of therapeutic doses of ampicillin (and amoxycillin) on estrogen levels during pregnancy may be less important than is commonly assumed.

Effects of ethinyloestradiol on plasma levels of pituitary gonadotrophins, testicular steroids and sex hormone binding globulin in normal men

Daily measurements of plasma FSH, LH, prolactin, testosterone, 17 beta-oestradiol and sex hormone binding globulin (SHBG) activity were made in eight healthy, normal men during treatment with oral ethinyloestradiol (EE2) in a dose of 30 micrograms/day for 5 days following a 5-day control period. No significant changes in plasma levels of FSH and prolactin during oestrogen treatment occurred. In contrast, plasma concentrations of both LH and testosterone showed a biphasic pattern. Following an initial suppression during the first 3 days of oestrogen treatment both LH and testosterone increased again to baseline values despite continuation of oestrogen administration. The secondary rise of both hormones was associated with (and probably resulted from) a nearly 100% increase in the plasma concentration of SHBG binding activity, and hence reduction of free testosterone index (FTI). Unlike testosterone, plasma 17 beta-oestradiol during EE2 administration did not show a biphasic pattern, but a progressive decline that was positively correlated with the fall in FTI. The rapidity of onset and magnitude of the observed rise in SHBG levels emphasizes the need for measurement of this binding protein (or the free testosterone fraction) in studies on feedback regulation of gonadotrophins employing exogenous EE2 in human males. The observed increase of SHBG to supraphysiological values suggests that currently employed EE2 doses in such studies may be less 'physiologic' than is often assumed.

Ovarian function in the ewe after active immunization against testosterone

The secretion rates of testosterone measured during the last half of the oestrous cycle in 2 Merino crossbred ewes with utero-ovarian autotransplants were 1.95 +/- 0.34 ng/min and 2.48 +/- 0.63 ng/min. The secretion rate of testosterone was not correlated with the secretion rate of oestradiol or androstenedione in either ewe. Welsh Mountain ewes were actively immunized against testosterone-3-(O-carboxymethyl)-oxime-bovine serum albumin (testosterone-3-BSA) or BSA alone (controls). Immunization against testosterone-3-BSA (5 ewes) resulted in anovulation (2 ewes) and the disruption of oestrous cycles and irregular ovulations (2 ewes). The ovaries showed morphological and endocrinological evidence of over-stimulation. Numerous large non-atretic follicles were present and in those ewes still ovulating the numbers of corpora lutea (ovulation rate) were increased. The concentrations of androstenedione and of oestradiol in the ovarian venous plasma were also markedly increased when compared to those in control ewes. The plasma binding capacity for steroids and the jugular venous concentrations of steroids were higher in immunized ewes. The binding capacity of follicular fluid for testosterone was similar to that of jugular venous plasma from the same ewe. These results show that immunization against testosterone-3-BSA leads to a disruption of ovarian cycles and ovarian over-stimulation.

Ovarian morphology and the concentration of steroids, and of gonadotrophins during the breeding season in ewes actively immunized against oestradiol-17 beta or oestrone

Ewes were actively immunized against oestrone-6-(O-carboxymethyl)-oxime-bovine serum albumin, 17 beta-oestradiol-6-(O-carboxymethyl)oxime-bovine serum albumin or bovine serum albumin (controls). All 4 control ewes, 1 of 5 oestradiol-immunized ewes and 1 of 5 oestrone-immunized ewes had regular oestrous cycles. The other animals displayed oestrus irregularly or remained anoestrous. The plasma concentrations of LH and, to a lesser degree, FSH were increased relative to those in control ewes on Days 11-12 after oestrus or a similar total period after progestagen treatment in ewes not showing oestrus. The ovaries were examined and jugular venous blood, ovarian venous blood and follicular fluid were collected at laparotomy on Days 9-10 of the oestrous cycle. The ovaries of immunized ewes were heavier than those of control ewes. There were no CL in 5 of the immunized ewes but in the other 5 there were more CL than in the control ewes. Ovaries from 4 of 5 oestrone-immunized ewes contained luteinized follicles, while ovaries from 4 of 5 oestradiol-immunized ewes contained very large follicles with a degenerated granulosa and a hyperplastic theca interna. Both types of follicles produced progesterone, detectable in ovarian venous plasma and production of other steroids, particularly androstenedione, was also increased. The steroid-binding capacity of plasma was increased in the immunized ewes. The binding capacity of follicular fluid for oestradiol-17 beta and oestrone was similar to that of jugular venous plasma from the same ewes. These results suggest that immunization against oestrogens disrupts reproductive function by interfering with the feedback mechanisms controlling gonadotrophin secretion.

Ovarian morphology and the concentration of steroids during the oestrus cycle of sheep actively immunized against androstenedione

Ewes were immunized against androstenedione-11 alpha-hemisuccinyl-bovine serum albumin (androstenedione-11-BSA) or BSA alone (controls). The ovaries were examined macroscopically and ovarian venous blood was collected at laparotomy by in-situ cannulation of the ovarian vein on Day 10 of the oestrous cycle, or by needle puncture of the ovarian vein 36 h after prostaglandin treatment. Follicular fluid was also collected from follicles greater than 5 mm diameter in some ewes. Ovaries and adrenal glands were collected and examined histologically. Oestrone, oestradiol-17 beta, androstenedione, testosterone and progesterone were measured by radioimmunoassays. Immunization against androstenedione-11-BSA was followed by an increase in the number of surface follicles greater than 3 mm in diameter and in ovulation rate. These changes were accompanied by an increased production of androgens (especially androstenedione) and of oestrogens during the preovulatory period. There were no observed changes in the adrenal cortex or pituitary glands, but the ovaries were heavier in immunized ewes and luteinized follicles were present in the ovaries of 1 of 4 immunized ewes. These results show that immunization against androstenedione-11-BSA leads to increased ovulation rate and suggest two possible mechanisms: (1) interference with the negative feedback effects of oestradiol-17 beta and/or (2) a reduction in the incidence of follicular atresia.

Effect of androstenedione on the oestrous cycle of the rat

The implantation of Silastic capsules containing androstenedione (release rate 63.2 +/- 4.4 micrograms/24 h) into 4-day cyclic rats resulted in a prolongation of the cycle (P less than 0.001), most rats showing 5-day cycles after the first, largely unaffected cycle. There was a reduction in ovulation rate (P less than 0.01) and lower serum LH levels on the morning of oestrus (P less than 0.01) but serum FSH levels were unaffected.

Plasma concentrations of luteinizing hormone and follicle-stimulating hormone during anoestrus in ewes actively immunized against oestradiol-17 beta, oestrone or testosterone

The concentrations of LH and FSH in jugular venous plasma were measured during anoestrus in control ewes and ewes actively immunized against 17 beta-oestradiol-6-(O-carboxymethyl)oxime--bovine serum albumin, oestrone-6-(O-carboxymethyl)oxime--bovine serum albumin or testosterone-3-(O-carboxymethyl)oxime--bovine serum albumin. During a 12 h sampling period, the basal level of LH and the frequency of LH pulses were significantly increased in all the immunized animals. The plasma FSH concentration was increased in two out of five oestradiol-immunized ewes and two out of three oestrone-immunized animals. The plasma FSH concentration in the testosterone-immunized animals was similar to the control values. Significant titres of antibodies to oestradiol-17 beta were found in all the immunized animals. It is suggested that binding of oestradiol-17 beta in the circulation by antibodies reduced the negative feedback action normally eserted by this steroid on LH secretion and, to a lesser extent, on FSH escretion. However, since the oestradiol antibody titres in the testosterone-immunized and oestrone-immunized ewes were considerably lower than those found in the oestradiol-immunized animals, it is possible that testosterone and oestrone, perhaps by acting as prehormones, could influence the negative feedback control by oestradiol-17 beta of gonadotrophin secretion in the anoestrous ewe.

Impaired estrogen-induced luteinizing hormone release in young women with anovulatory dysfunctional uterine bleeding

Spontaneous ovarian activity, as reflected by the urinary excretion of total estrogen and pregnanediol measured serially (thrice weekly) over a period of 3-4 months, was studied in nine young women (15-27 yr old) with a history of dysfunctional uterine bleeding of at least 2-yr duration. Results were compared to those obtained in sex regularly menstruating women, aged 23-45 yr. All control women had ovulatory cycles, but seven of the nine patients with DUB failed to ovulate during at least three consecutive cycles. The profiles of urinary total estrogen excretion in these seven subjects were consistent with regular follicular development, but the follicular phase was prolonged and the amount of estrogen excretion increased, as compared to controls. In four of these seven patients, the endometrium had previously shown cystic glandular hyperplasia. Although the release of LH and FSH after injection of 50 micrograms synthetic LRH was normal, the surge of LH induced in response to exogenous estrogen (200 micrograms ethinylestradiol/day for 3 days) was significantly (P less than 0.005) lower in the patients (16.2 +/- 3.7 mU/ml) than that of control women )35.0 +/- 5.5 mU/ml). It is concluded that the failure to ovulate in young women with anovulatory dysfunctional uterine bleeding is due to inadequate release of LH in response to estrogen. The results support the hypothesis that the basic defect in these women may be a decrease of hypothalamic sensitivity to positive feedback.

Ovulation and lambing rates in ewes actively immunized against androstenedione

In ewes immunized against androstenedione, ovulation rate was increased (P less than 0.001) although the number of live lambs/nursing ewe (1.37), but not the sex ratio (10 females:1 male), was similar to that of controls (1.33).

Changes in volume, total protein and ovarian steroid concentrations of peritoneal fluid throughout the human menstrual cycle

Peritoneal fluid was aspirated during laparoscopy from normal women at various stages of the menstrual cycle. The volume of the fluid was found to be influenced by the stage of the cycle, rising from an early proliferative mean value of 0·8 ml to a mean volume of 18·7 ml after ovulation and decreasing again to a mean volume of 5·4 ml in the late secretory phase. The mean volume of peritoneal fluid obtained from women using the contraceptive pill was 0·8 ml, whereas only negligible amounts of fluid were aspirated at laparotomy from the peritoneal cavity of men.

Despite marked changes in volume, the total protein content of the peritoneal fluid (± 60% of the concentration measured in plasma) remained fairly constant throughout the cycle, although a slightly, but significantly, lower value was found in the late proliferative phase. After ovulation the concentration of oestradiol and progesterone in the peritoneal fluid was higher than in plasma in the majority of cases, suggesting that some follicular fluid had drained into the peritoneal cavity at that time. Progesterone, in contrast to oestradiol, was also found in higher concentrations in peritoneal fluid than in plasma before ovulation.

These results suggest that the volume and ovarian steroid concentration of peritoneal fluid are influenced by cyclic ovarian activity. At least two mechanisms may account for these observations: changes possibly effected by oestradiol in vascular permeability leading to a change of inflow and outflow equilibrium at the level of the peritoneal membranes and ovarian–peritoneal transfer of fluid after and possibly also before follicular rupture.

Pituitary-ovarian relationships in polycystic ovary syndrome

The spontaneous pattern of pituitary gonadotropins and ovarian steroids and their response to dynamic tests were measured in 12 women with polycystic ovarian syndrome (PCO) and the results compared to those from 6 normal women during the early follicllar phase of the cycle (controls). As judged by serial measurements of urinary total estrogen and pregnanediol over a 12-week period, in PCO patients 75% of cycles were anovulatory (anovulatory PCO) as compared to 100% ovulatory in controls. The basal concentrations of LH, androstenedione and estrone were significantly higher and the concentration os FSH significantly lower in anovulatory PCO than in the controls (P less than .05). In PCO patients the concentration of LH was lower following an ovulatory cycle than that following a period of anovulation. Negative and positive feedback responses to an estrogen provocation test (200 microgram ethinyl estradiol per day for 3 days) were normal in anovulatory PCO although the LH peak occurred 24 h earlier than in the controls. The amplitude of the pulses of LH was significantly greater in anovulatory PCO than in the controls and was suppressed in both groups after ethinyl estradiol. The peak release of LH in response to 56 microgram LRF in ovulatory PCO was similar in controls but LH responses in anovulatory PCO were significantly greater. It is suggested that the abnormalities in gonadotropin secretion in PCO are secondary to excessive and prolonged extraglandular production of estrogen from androstenedione.

Failure of positive feedback

Failure of the hypothalamic-pituitary unit to release LH in response to oestrogen may be encountered with or without associated disturbance of negative feedback. Such positive feedback failures can be detected with the aid of an oestrogen provocation test. Application of this test in women presenting with anovulatory cycles permits one to distinguish between an hypothalamic or ovarian cause (e.g. deficient follicular development) for anovulation. In women with infrequent or absent menstruation and infertility an oestrogen provocation test, combined with basal gonadotrophin and prolactin measurement and pituitary response to LH-RH, may prove to be useful in selecting the appropriate treatment for induction of ovulation.