Effect of metoclopramide induced hyperprolactinaemia on the gonadotrophic response to oestradiol and LRH

Mechanism of anovulation in hyperprolactinemic amenorrhea determined by pulsatile gonadotropin-releasing hormone injection combined with human chorionic gonadotropin

OBJECTIVE

To clarify the mechanism of anovulation in hyperprolactinemic anovulatory women by subcutaneous (SC) pulsatile GnRH injection.

DESIGN

Prospective clinical study.

SETTING

Studies were made on at the Department of Obstetrics and Gynecology, the University of Tokushima, School of Medicine.

PATIENTS

Six hyperprolactinemic (group 1) and 7 normoprolactinemic (group 2) anovulatory patients were studied.

INTERVENTIONS

After examinations of pulsatile secretion of LH, the GnRH test, thyrotropin-releasing hormone test and estrogen test, pulsatile GnRH treatment (20 micrograms/2 hours SC) was performed. Two protocols were tested on each patient. In the non-hCG protocol, GnRH treatment was continued until ovulation. In the hCG protocol, 5,000 IU of hCG was injected to induce ovulation when follicles were fully mature.

MAIN OUTCOME MEASURE

The rates of follicular maturation and ovulation, serum E2 and P in the two groups.

RESULTS

Pulsatile LH secretion was impaired in both groups. LH release 48 hours after estrogen injection was impaired in group 1 but not in group 2. Follicles matured on pulsatile GnRH treatment in all cycles in both groups. However, with the non-hCG protocol, ovulation occurred in only 17% of group 1, but in 89% of group 2. With the hCG protocol ovulation occurred in all cycles in both groups.

CONCLUSIONS

The main cause of anovulation is impaired gonadotropin pulsatility and derangement of the estrogen-positive feedback effect on LH secretion in hyperprolactinemic patients, their ovarian response to gonadotropin being well maintained. Subcutaneous pulsatile GnRH therapy combined with hCG can be used as an alternative to bromocriptine treatment for induction of ovulation in these patients.

Induction of ovulation: historical aspects

The cornerstone of the conquest of infertility was laid in the beginning of this century. It took, however, nearly 80 years of work of many scientists from all over the globe to slowly unravel the puzzle of nature's most guarded secret, the control of the reproductive processes. The estimated population size of women between the ages 19 and 34 years in the developed world in 1990 will be about 130 million. If we assume that at least 8% will be infertile, then the pool of the infertile population will be above 10 million, with about 700,000 new patients entering this pool every year between the years 1990 and 1995. In the past only about 40% of infertile patients benefited from ovulation induction regimens. With the advent of assisted reproduction this population increased to about 80%. With the use of gonadotrophins for induction of superovulation in normally ovulating women conceptual changes in treatment regimens and monitoring schemes had to be introduced. It is obvious that the primary task of infertility clinics is to diagnose the main cause (or causes) of infertility in each couple in order to be able to institute appropriate therapy within a reasonable time. We have attempted to review briefly the regulation of follicular development, particularly with regard to new findings demonstrating the potentiating effect of growth hormone and/or various growth factors on ovarian sensitivity to FSH. This new knowledge, as well as availability of potent GnRH analogues, will evidently refine our clinical approach to treatment of functional infertility. Continuous advances in the understanding of mechanisms regulating reproductive processes and the better recognition of underlying causes of infertility will lead to the optimal choice of first-, second- and third-line routine therapies which will apply to the majority of patients. Furthermore, it will become possible to design tailor-made ovulation-inducing protocols for specific patients who do not respond properly to the routine treatment.

Treatment of hirsutism in polycystic ovary syndrome with bromocriptine

The value of bromocriptine in the treatment of hirsutism in polycystic ovary syndrome (PCO) was assessed subjectively and photographically in a double-blind trial in 22 women studied for 1 year. Menstrual frequency was recorded. Circulating concentrations of oestradiol, oestrone, testosterone, androstenedione, and sex hormone binding globulin (SHBG) were determined before treatment and after 6 and 12 months therapy. On the same occasions gonadotrophin concentrations (mean of 24 samples) and their response to 100 micrograms LHRH were determined. No evidence was found to support a therapeutic role for bromocriptine in the treatment of hirsutism or menstrual regulation in PCO. No biochemical changes were seen specific to bromocriptine therapy.

The acute effects of a dopamine antagonist (domperidone) on luteinising hormone, follicule stimulating hormone, prolactin and thyrotrophin secretion in polycystic ovarian syndrome: differential effect of ovulation

An alteration of the hypothalamic dopaminergic regulation of LH secretion has been implicated in the abnormal LH secretion of polycystic ovarian syndrome (PCOS). To investigate this, the acute effect of dopamine (DA) receptor blockade on LH, FSH, PRL and TSH secretion was determined. No effect was observed on either LH or FSH secretion in the PCOS patients or in normal women and LH pulsatility appeared to be maintained. When the PCOS patients were divided into those who ovulated in the preceding cycle and those who were anovulatory, it was observed that the ovulatory patients had a normal PRL and TSH response; whereas in the anovulatory patients, the PRL rise was blunted and the TSH response was absent. We conclude that this study gives no evidence to support the hypothesis of altered hypothalamic DA regulation of LH secretion in PCOS. The lack of LH response to DA blockade suggests that a physiological role of DA in the control of LH secretion seems unlikely as determined under these experimental conditions. The differences in PRL and TRH response may reflect anovulation rather than a fundamental abnormality in PCOS.