Action of MER-25 and of clomiphene on the human ovary

Sequential use of clomiphene citrate and human menopausal gonadotropin in ovulation induction

Kistner RW, 1976 · Fertil Steril

In an effort to diminish the incidence of multiple pregnancy, ovarian hyper-stimulation syndrome, and the excessive cost of human menopausal gonadotropin (HMG) administration, a sequence of Clomid-HMG-human chorionic gonadotropin (HCG) was used in 80 patients with infertility due to prolonged amenorrhea. Criteria for this therapeutic regimen were: (1) normal seminal fluid analysis and postcoital test; (2) lack of withdrawal bleeding from progesterone following amenorrhea of more than 6 months' duration; (3) normal x-ray of the sella turcica and visual fields; (4) low serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels; (5) normal endoscopic examination; and (6) lack of response to clomiphene in excessive dose (200 mg daily for 5 days) or prolonged dose (100 mg daily for 10 days) with or without HCG, or apparent ovulatory response to the above sequence for five or six consecutive cycles without pregnancy. Clomiphene was administered in a dose of 100 mg daily for 7 days. HMG was then given in the following manner: two ampules daily for 4 days, then one ampule daily for 2 days (75 IU of FSH and 75 IU of LH/ampule). After a 24-hour interval without treatment, 10,000 IU of HCG were given and 2000 IU of HCG 4 days later. Twenty-three pregnancies occurred in 80 patients. However, 15 of the first 25 patients became pregnant--in these patients the only abnormality noted was lack of ovulation. Six additional pregnancies occurred subsequent to one or more unsuccessful cycles. Multiple pregnancies occurred in only two patients (twins delivered at 32 weeks in one and an abortion of five fetuses at 20 weeks in another). However, multiple pregnancy did not occur in any patient whose urinary estrogen level was monitored and in whom the level was 100 mug or less when the HCG was given. The ovarian hyperstimulation syndrome did not occur in any patient.

FURTHER OBSERVATIONS ON THE EFFECTS OF CLOMIPHENE CITRATE IN ANOVULATORY FEMALES

Kistner RW, 1965 · Am J Obstet Gynecol

INDUCTION OF OVULATION WITH CLOMIPHENE CITRATE

Naville AH et al., 1964 · Fertil Steril

CLOMIPHENE CITRATE: FURTHER OBSERVATIONS ON ITS USE IN INDUCTION OF OVULATION IN THE HUMAN AND ON ITS MODE OF ACTION

Roy S et al., 1963 · Fertil Steril

Induction of ovulation in the human has been of considerable research interest for several decades. Various hormonal regimens and other procedures have been tried in the past.1 • 2 In spite of all these trials, the problem of ovulatory failure remains a frustrating dilemma for the physician. Recently, the induction of ovulation with clomiphene citrate in about 70% of anovulatory women was reported by our group.3- 6 It was felt that an important breakthrough in this difficult field of endeavor was at hand. 7- 9 Our observations have been confirmed by other groups of investigators.10- 12 The present report embodies a detailed analysis of the results of administration of this agent to 200 women, of whom 179 were anovulatory. The results of our studies on the probable mode of action of this drug are also discussed.

Evidence for a hypothalamic site of action of clomiphene citrate in women

Kerin JF et al., 1985 · J Clin Endocrinol Metab

To examine the site of action of clomiphene citrate (CC), LH and FSH pulsatile amplitude, frequency, and responsiveness to GnRH (10 micrograms, iv) were studied in 11 women during the early follicular phase of the menstrual cycle. Six women received CC (150 mg/day) on cycle days 2, 3, and 4, while 5 women received placebo tablets. Blood samples were drawn at 10-min intervals for 8 h before and after the treatment regimen on cycle days 2 and 5, respectively. All women treated with CC had multiple follicular development, as determined by ultrasound. Peripheral levels of estradiol did not change after CC treatment, while progesterone levels decreased slightly. Mean levels of LH increased from 7.5 +/- 0.9 (+/- SEM) to 10.7 +/- 1.4 mIU/ml (P less than 0.05), and FSH increased from 6.7 +/- 0.9 to 10.1 +/- 0.9 mIU/ml (P less than 0.01). After exposure to CC, the pulse frequency of LH during an 8-h period increased significantly (3.3 +/- 0.7 on day 2 vs. 6.8 +/- 0.8 on day 5; P less than 0.01), while the pulse frequency of FSH increased from 3.8 +/- 0.6 to 5 +/- 1.4, as determined by computer pulse analyses. The pulse amplitude of LH and FSH was not significantly altered. In the placebo-treated group, neither pulse amplitude nor pulse frequency changed significantly between cycle days 2 and 5. Pituitary sensitivity to exogenous GnRH did not change after CC treatment. Since the pulsatile frequency of LH is governed by hypothalamic influences, these findings provide compelling evidence for a hypothalamic site of action for CC, probably by inducing an increase in the frequency of GnRH secretion.

Experience with induction of ovulation

MacLeod SC et al., 1970 · Am J Obstet Gynecol

One hundred and thirty-five patients diagnosed as ovulatory failure have been treated in our clinic since 1966. One hundred and eighteen of these have been treated with clomiphene citrate, or more recently, its cisisomer, and 17 patients with long-standing secondary amenorrhea or primary amenorrhea have been treated with human menopausal gonadotropins, in combination with human chorionic gonadotropins. Of the latter group, 14 of the 17 were shown to be capable of response to exogenous gonadotropins and 12 of these ovulated and 7 (50 per cent) became pregnant. The over-all ovulatory rate with clomiphene citrate or its cisisomer was 78 per cent, with a pregnancy rate of 31 per cent. The results of our present investigation with clomiphene citrate in 10 and 20 mg. dosage are presented in detail, and compared with our previous experience with clomiphene. It appears that cisclomiphene 20 mg. is as effective as clomiphene citrate 100 mg., but has the decided advantage of fewer side effects associated with its use. With the human menopausal gonadotrophins, no major complications, such as ovarian overstimulation or multiple pregnancies, were encountered, and we feel this is attributed to careful selection of patients and daily tracking of total urinary estrogens.

Antiestrogenic effect of clomiphene citrate: correlation with serum estradiol concentrations

Maxson WS et al., 1984 · Fertil Steril

The antiestrogenic effect of clomiphene citrate (CC) on cervical mucus was evaluated in women receiving 150 mg CC daily for 5 days. Daily cervical mucus scores and serum estradiol (E2) concentrations were determined in control (n = 25) and CC (n = 24) cycles. E2 concentrations were significantly higher in the CC-treated women (mean +/- standard error of the mean, 1254 +/- 102 pg/ml versus 337 +/- 18 pg/ml, P less than 0.0001). Despite supraphysiologic E2 concentrations, however, cervical mucus scores were significantly reduced in the CC-treated group (P less than 0.01). These data indicate that CC exerts a direct suppressive effect on cervical mucus despite markedly increased E2 concentrations.