Acute effects of bromocriptine on gonadotropin secretion in polycystic ovary syndrome

Polycystic ovary syndrome and hyperprolactinemia are distinct entities

The aims of the present study were to identify the cause of hyperprolactinemia in polycystic ovary syndrome (PCOS) and to compare prolactin (PRL) levels between PCOS women without hyperprolactinemia and women with insulin resistance and without PCOS. A group of 82 women (age: 27.1 +/- 7.6 years) with PCOS was included in the study. Their PRL levels were measured and compared with those of women with insulin resistance without PCOS (controls; n = 42; age: 29.2 +/- 8.2 years). Among the 82 PCOS women, 13 (16%) presented high PRL levels (103.9 +/- 136.0 microg/l). The causes of hyperprolactinemia were: pituitary tumor (responding to cabergoline) in nine cases (69%; PRL range: 28.6 - 538 microg/l); oral hormonal contraceptive treatment in two cases (15%; PRL: 46 and 55 microg/l, respectively); and use of buspirone and tianeptine in one case (8%; PRL: 37.1 microg/l); one case (8%; PRL: 34.4 microg/l) had macroprolactinemia. In drug-induced hyperprolactinemic patients PRL levels normalized after treatment interruption. The average PRL level in the 69 remaining patients was 12.1 +/- 5.5 microg/l, a value not statistically different from that of the control group (11.8 +/- 4.9 microg/l). This result leads us to conclude that PCOS patients with increased PRL levels must be investigated for other causes of hyperprolactinemia, because hyperprolactinemia is not a clinical manifestation of PCOS.

The chronic administration of cabergoline normalizes androgen secretion and improves menstrual cyclicity in women with polycystic ovary syndrome

OBJECTIVE

To investigate whether the administration of the long-lasting dopaminergic drug, cabergoline, improves endocrine and clinical features of women with polycystic ovary syndrome (PCOS).

PATIENTS

Twenty-nine women participated in the study: 14 women with clinical and endocrinologic features of PCOS and 15 age- and weight-matched normal cycling women. Each subject was assigned randomly to receive either a tablet of cabergoline at the dose of 0.5 mg/wk or placebo for 4 months. Sixteen subjects (PCOS: n = 8; controls: n = 8) received cabergoline, whereas 13 (PCOS: n = 6; controls: n = 7) received placebo.

INTERVENTIONS

Both before and during the 4th month of treatment, blood samples were collected every 10 minutes from 9:00 A.M. to 3:00 P.M., 3 to 7 days after spontaneous or medroxy-progesterone acetate (MPA; 5 mg daily for 5 days)-induced menses. Follicle-stimulating hormone and androgen levels were measured in the basal samples, whereas LH levels were measured in all samples.

MAIN OUTCOME MEASURES

Menstrual cyclicity, LH pulsatility, and circulating levels of FSH, PRL, E2, total T, free T, androstenedione, 17 alpha-hydroxyprogesterone, DHEAS, and sex hormone-binding globulin.

RESULTS

Both in controls and in PCOS-affected women, cabergoline administration blunted plasma PRL levels without affecting LH pulsatility. Androgen levels were reduced in controls and normalized in PCOS. Cabergoline, but not placebo, induced menses reappearance in amenorrheic and a normalization of menstrual cyclicity in oligoamenorrheic women with PCOS.

CONCLUSIONS

The administration of cabergoline is capable to normalize androgen levels and to improve menstrual cyclicity in PCOS-affected women. Cabergoline may represent an useful treatment for menstrual irregularities of PCOS patients.

Acute effects of L-dopa and bromocriptine on serum PRL, LH and FSH levels in patients with hyperprolactinemic and normoprolactinemic polycystic ovary syndrome

We have investigated the importance of the dopaminergic control of gonadotropin secretion by studying LH, FSH and PRL responses to L-dopa and bromocriptine in patients with polycystic ovary syndrome (PCOS). Both L-dopa and bromocriptine administration were followed by a statistically significant decrease in LH in the hyperprolactinemic PCO patients (compared to the normoprolactinemic subgroup - p less than 0.01 and control group - p less than 0.05); the decline was proportional to the basal level of LH. A significant positive correlation between basal LH levels and maximum net decrease of LH was observed after administration of both agents (p less than 0.01). Although both subgroups of PCO patients showed a similar decrease in PRL levels it was statistically significant only in the normoprolactinemic patients (p less than 0.01). Prolactin sensitivity to the inhibitory effect of bromocriptine and L-dopa showed a significant correlation with the basal PRL level (p less than 0.01). The response of serum FSH was variable and not significant. These results suggest that a reduction of an inhibitory influence of hypothalamic dopamine might be a cause of inappropriately elevated LH and PRL levels found in patients with polycystic ovary syndrome and hyperprolactinemia.