The effect of bromocriptine on gonadotropin and steroid secretion in polycystic ovarian disease

Prolactin in Polycystic Ovary Syndrome: Metabolic Effects and Therapeutic Prospects

Polycystic ovary syndrome (PCOS) is the most prevalent endocrine and metabolic disorder in premenopausal women, characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovaries. Patients frequently present comorbidities, including obesity, insulin resistance, and impaired glucose and lipid metabolism. The diverse clinical presentation may mimic various endocrine disorders, making the diagnosis challenging in some clinical circumstances. Prolactin (PRL) is a recommended biomarker in the initial diagnostic workup to rule out hyperprolactinemia (HPRL). The traditional role of PRL is linked to lactation and the reproductive system. Recent research highlights PRL's emerging role in metabolic homeostasis. PRL influences metabolism directly by interacting with the pancreas, liver, hypothalamus, and adipose tissue. Its influence on an individual's metabolism is intricately tied to its serum concentration. While deficient and very high levels of PRL can negatively affect metabolism, intermediate-normal to moderately high levels may promote metabolic health. In women with PCOS, PRL levels may be altered. Research results on different aspects of the relationship between PCOS and the impact of various levels of PRL on metabolic homeostasis are limited and inconsistent. In this narrative literature review, we comprehensively examined data on serum PRL levels in PCOS patients. We investigated the correlation between a favorable metabolic profile and serum PRL levels in this population. Furthermore, we explored the concept of beneficial PRL effects on metabolism and discussed the potential therapeutic application of dopamine agonists in PCOS treatment. Lastly, we emphasized several promising avenues for future research in this field.

Obesity and the Risk of Infertility, Gestational Diabetes, and Type 2 Diabetes in Polycystic Ovary Syndrome

This review describes the relationship between obesity and the most common reproductive (infertility) and metabolic (gestational diabetes mellitus [GDM] and type 2 diabetes mellitus [T2DM]) consequences in polycystic ovary syndrome (PCOS). It also describes the vital role of lifestyle management for PCOS. PCOS is a heterogeneous endocrine disorder common in reproductive-age women. Consensus on the exact etiological mechanisms of PCOS is unreached. Overweight or obesity is present in at least 60% of the PCOS population, but the condition occurs irrespective of BMI, with excess BMI increasing both the prevalence and severity of clinical features. Use of lifestyle therapies (nutrition, physical activity, and/or behavioral) for the prevention and management of excess weight gain, infertility, GDM, and T2DM is a vital component of best-practice PCOS care. Lifestyle management is recommended for all women with PCOS as the first-line treatment with or without medications. Due to a lack of high-quality trials demonstrating the efficacy of specific lifestyle approaches, PCOS lifestyle recommendations are as those for the general population. This review summarizes current knowledge relating to obesity and its impact on fertility, GDM, and T2DM. It also summarizes the lifestyle recommendations to best manage these conditions in women with PCOS and obesity.

PCOS and Hyperprolactinemia: what do we know in 2019?

Polycystic ovary syndrome (PCOS) and hyperprolactinemia (HPRL) are the two most common etiologies of anovulation in women. Since the 1950s, some authors think that there is a pathophysiological link between PCOS and HPRL. Since then, many authors have speculated about the link between these two endocrine entities, but no hypothesis proposed so far could ever be confirmed. Furthermore, PCOS and HPRL are frequent endocrine diseases and a fortuitous association cannot be excluded. The evolution of knowledge about PCOS and HPRL shows that studies conducted before the 2000s are obsolete given current knowledge. Indeed, most of the studies were conducted before consensual diagnosis criteria of PCOS and included small numbers of patients. In addition, the investigation of HPRL in these studies relied on obsolete methods and did not look for the presence of macroprolactinemia. It is therefore possible that HPRL that has been attributed to PCOS corresponded in fact to macroprolactinemia or to pituitary microadenomas of small sizes that could not be detected with the imaging methods of the time. Recent studies that have conducted a rigorous etiological investigation show that HPRL found in PCOS correspond either to non-permanent increase of prolactin levels, to macroprolactinemia or to other etiologies. None of this recent study found HPRL related to PCOS in these patients. Thus, the link between PCOS and HPRL seems to be more of a myth than a well-established medical reality and we believe that the discovery of an HPRL in a PCOS patient needs a standard etiological investigation of HPRL.

Obesity and PCOS: the effect of metabolic derangements on endometrial receptivity at the time of implantation

Successful embryonic implantation is the result of a receptive endometrium, a functional embryo at the blastocyst stage and a synchronized dialog between maternal and embryonic tissues. Successful implantation requires the endometrium to undergo steroid-dependent change during each menstrual cycle, exhibiting a short period of embryonic receptivity known as the window of implantation. The term "endometrial receptivity" was introduced to define the state of the endometrium during the window of implantation. It refers to the ability of the endometrium to undergo changes that will allow the blastocyst to attach, penetrate, and induce localized changes in the endometrial stroma. These changes are metabolically demanding, and glucose metabolism has been proven to be important for the preparation of the endometrium for embryo implantation. Obesity and polycystic ovary syndrome (PCOS) represent 2 common metabolic disorders that are associated with subfertility. The aim of this review is to summarize the effect of obesity and PCOS on endometrial receptivity at the time of implantation. Focus will be on metabolic alterations that regulate decidualization, including glucose metabolism, hyperinsulinemia, and hyperandrogenism.

Induction of Ovulation with Clomiphene Citrate Versus Clomiphene with Bromocriptine in PCOS Patients with Normal Prolactin: A Comparative Study

INTRODUCTION

Polycystic ovarian syndrome (PCOS) is the main cause of anovulatory infertility. Various combination of drugs have been tried to induce ovulation in PCOS patients with varied result. So, this study was planned to compare the effect of bromocriptine combined with Clomiphene Citrate and Clomiphene Citrate alone, in patients of polycystic ovarian syndrome with normal prolactin level.

MATERIALS & METHODS

On the basis of inclusion and exclusion criteria, seventy four PCOS patients with normal prolactin level (< 20 ng/ml) and BMI between 20-30 were randomly assigned into two groups. One group (n=38) received 50 mg clomiphene citrate (CC) from day3 to day7. The other group (CC+Bcrt) was given 50 mg of clomiphene citrate from day3 to day7 along with 0.8mg of bromocriptine daily for full cycle (n=36). Both the groups were treated for 3 cycles. The outcomes were measured by the hormonal status, follicular size, ovulation rate and pregnancy outcomes.

RESULTS

The serum prolactin level was normal in both the groups before treatment. After 3 cycles the prolactin level decreased in (CC+Bcrt) group (p< 0.01). Follicular development (size >15mm) was observed in 30 patients (78.9%) in CC group and 28 patients (82.3%) in CC+Bcrt group. There was no significant change in hormonal status (LH, FSH and Estradiol) of both the groups. The rate of ovulation was 69.4% in CC group and 75.8% in CC+Bcrt group. During the treatment period, nine patients in CC group and seven patients in CC+Bcrt group became pregnant.

CONCLUSION

There is no added benefit of bromocriptine with clomiphene citrate as compared to clomiphene alone in ovulation induction as well as pregnancy outcomes in PCOS patients with normal prolactin.

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.

A prospective, double-blind, randomized, placebo-controlled clinical trial of bromocriptin in clomiphene-resistant patients with polycystic ovary syndrome and normal prolactin level

OBJECTIVE

The purpose of this study was to examine the effects of of bromocriptin combined with clomiphene citrate in clomiphene-resistant patients with polycystic ovary syndrome and normal prolactin level.

DESIGN

Prospective, double-blind, controlled study.

SETTING

University teaching hospital.

PATIENTS

One hundred polycystic ovary patients and normal prolactin (PRL) who were clomiphene citrate resistant.

INTERVENTIONS

Treatment group received 150 mg clomiphene citrate on days 5-9 and 7.5 mg bromocriptin continuously. Control group received the same protocol of clomiphene citrate combined with placebo.

MAIN OUTCOME MEASURES

Hormonal status, follicular monitoring, ovulation rate.

RESULTS

Follicular development (follicular size greater than 15 mm) was observed in 12 (25.5%) and eight (15.1%) women in treatment and placebo group respectively ( P=0.29). The serum prolactin level was within normal limits in all patients before treatment. After 3 and 6 months of treatment with bromocriptin, there was a significant decrease in serum level of prolactin ( P=0.000001). No any significant differences was seen in ovulation, and serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), dehydroepiandrosterone sulfate (DHEAS), progesterone (P) between treatment and placebo group after treatment.

CONCLUSIONS

The only significant effect of long-term bromocriptin therapy in clomiphene citrate resistant polycystic ovary women was to lower the serum prolactin concentration. It was also concluded that 10-15% of patients with polycystic ovaries experienced occasional ovulatory cycles and pregnancy whether or not they were on treatment.

Polycystic ovary syndrome and ovulation induction

Before initiating treatment to induce ovulation in cases of PCOS, an appropriate evaluation of the patient and her partner, based on individual considerations, is important to optimize outcome. For obese patients with PCOS, weight-loss measures should be pursued before pharmacologic treatment is initiated. For most patients, the pharmacologic agent of choice to induce ovulation is clomiphene citrate, alone or in combination with a glucocorticoid. Treatment with metformin, alone or in combination with clomiphene citrate, may also be beneficial. For patients not responsive to clomiphene citrate, injectable gonadotropin treatment is usually warranted, although, depending on individual circumstances, laparoscopic ovarian drilling may be appropriate.

Polycystic ovary syndrome and hyperprolactinemia

Analysis of the evidence linking PCOS and hyperprolactinemia suggests that these conditions have independent origins. Elevated prolactin serum levels are documented in the early studies of patients with polycystic ovaries. However, recent investigators using serial serum sampling have excluded transient elevations of prolactin and have shown a less frequent association of these disorders. Treatment of individuals with both PCOS and hyperprolactinemia is distinct from the management of the individual with only one of these conditions. Upon evaluating the therapeutic alternatives for dysfunctional uterine bleeding and hirsutism in these patients, the effect of exogenous estrogen and progesterone on the secretion of prolactin must be considered. The addition of a dopamine agonist (e.g., bromocriptine or cabergoline) to a regimen of clomiphene citrate must also be considered as ovulation induction options for these women. Finally, future discoveries about the relationship between PCOS and hyperprolactinemia will require a better understanding of how the hypothalamus regulates the pituitary secretion of LH and prolactin.

Polycystic ovary syndrome: clinical perspectives and management

The polycystic ovary syndrome (PCOS) is a common hyperandrogenic disorder and is characterized by a constellation of signs and symptoms often in association with a family history of hyperandrogenism and/or PCOS. It is often associated with hyperinsulinism and insulin resistance, which puts patients at risk for possible potential complications including type 2 diabetes mellitus and cardiovascular disease. Clinical signs may be subtle, and biochemical markers most often include an elevation of free testosterone (T) and possibly dehydroepiandrosterone sulfate (DHEAS). The diagnosis should be sought in any woman with hyperandrogenic features so that appropriate treatment may be used. There is often a good therapeutic response of the hirsutism, acne, or oligomenorrhea associated with PCOS. The new modalities that increase insulin sensitivity as well as weight reduction in the obese woman with PCOS may potentially be useful in modifying the potential later complications of this common endocrinopathy of young adult women.

Role of GnRH drive in the pathophysiology of polycystic ovary syndrome

Polycystic ovary syndrome may result from multiple mechanisms, but full expression of the PCO syndrome with hyperandrogenic anovulation depends upon sustained LH drive and relative FSH deficiency. We have described possible intrinsic and extrinsic factors capable of modifying the hypothalamic-pituitary-ovarian axis. Available evidence suggests the presence of an intrinsic alteration in GnRH-LH drive. The long-term natural history of HAA is variable and depends on several factors including obesity, aberrations in insulin action, intrinsic ovarian function, and end-organ responsiveness to androgens. Figure 1 presents a conceptualization of the pathogenesis of PCOS diagramming the multiple modulators of its expression. Long-term suppression of androgens when fertility is not desired should modify the full expression of the PCO syndrome. It is important to appreciate that therapy with oral contraceptive agents has few drawbacks and many immediate and potential long-term benefits for women with HAA. This therapy may be of greatest benefit when started in adolescence prior to the progression of obesity, hirsutism, and thecal-stromal hyperplasia. Women with HAA represent a large subgroup of patients who require individualization of their health care with sensitivity to issues surrounding anovulation, obesity, hirsutism, and infertility.

Resistance of gonadotropin releasing hormone drive to sex steroid-induced suppression in hyperandrogenic anovulation

Women with hyperandrogenic anovulation (HAA) exhibit increased GnRH drive, as evidenced by a faster LH pulse frequency that slows in response to progestin-induced opioidergic tone. To determine whether increased GnRH-LH drive in HAA reflects altered sex steroid exposure caused by chronic anovulation or is an intrinsic hypothalamic attribute, we compared the pulsatile LH response to oral contraceptive (OC)-induced suppression in seven women with HAA, with that of seven eumenorrheic women (EW). LH levels were determined at 10-min intervals for 12 h after 19-21 days of OC use and 5-7 days after cessation. Testosterone, androstenedione, estradiol, FSH, and LH levels were determined at weekly intervals before, during, and after OC use. LH pulse number/12 h was higher (P < 0.001) in HAA during and after OCs, when compared with that of EW. Mean LH was increased in HAA before, during, and after OCs. Testosterone, androstenedione, and estradiol levels were higher in HAA before OCs, but they decreased to similar levels during OC use in both groups. FSH concentrations were similar before and during OCs but rose more after cessation of OCs in EW. These findings indicate that GnRH drive in HAA is resistant to OC-induced suppression and, therefore, could be an intrinsic hypothalamic attribute.

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.

Neuroendocrinology of the polycystic ovary syndrome

The clinical and biochemical heterogeneity of the PCOS is mirrored by the range of neuroendocrine disturbances described in women with PCOS. An increased serum LH concentration is a common, although not ubiquitous, feature and occurs primarily as a result of an increase in the amplitude of pulsatile LH, and presumably GnRH, secretion. The frequency of pulsatile GnRH secretion may, however, be increased in certain patients and may conceivably increase LH bioactivity by altering glycosylation of the molecule. Vigorous debate continues as to whether the observed changes in gonadotrophins are a primary abnormality or occur secondary to alterations in peripheral steroid concentrations. The proponents of the frequency hypothesis point to the discordant changes in gonadotrophin secretion that may be induced by rapid frequency exogenous GnRH stimulation in patients with hypogonadotrophic hypogonadism. Those who believe that the inappropriate gonadotrophin secretion is a secondary phenomenon argue that manipulation of peripheral steroid levels, by either administration of oestrogen/progesterone, induced ovulation or ovarian diathermy, may correct the disturbance of gonadotrophin secretion, which is therefore presumably a consequence of changes in ovarian steroid feedback signals. The weight of evidence at present suggests that the inappropriate gonadotrophin secretion is usually a secondary abnormality, although there may be groups of patients with a primary increase in GnRH pulsatility. The search for a unifying neuroendocrine disturbance in PCOS has been frustrated by the inability to find consistent evidence of disordered central dopaminergic, opioidergic, noradrenergic or serotoninergic pathways. Those abnormalities which have been uncovered appear to be secondary to chronic anovulation rather than of primary pathological import, and emphasize the central importance of the ovary as culprit rather than victim in PCOS.

Hormonal and clinic evaluation of patients with moderate body hair growth

Plasma prolactin (PRL), gonadotropins (FSH, LH), estradiol-17 beta (E2), progesterone (P), total testosterone (T), sex steroid binding protein (SBP), T/SBP index, cortisol (F), 17-OH-progesterone (17OH-P), dehydroepiandrosterone sulphate (DHEA-S) and androstenedione (A), were measured in 50 fertile non-obese women presenting with moderate body hair growth and in 30 matched controls. DHEA-S and PRL were significantly higher (P < 0.002, P < 0.001, respectively) and SBP was lower (P < 0.001) in patients than in controls. Regression analyses showed that PRL levels were independent of the other parameters, while a negative correlation was found between DHEA-S and SBP values. Since the decision to treat a woman with mild body hair growth is usually a clinical one, PRL behaviour has to be taken into account before deciding the type of treatment. Clinical improvement was observed in subjects treated with ethynylestradiol plus desogestrel or plus cyproterone acetate, so as to produce an increase in SBP rather than a decrease in DHEA-S.

Increased dopamine turnover in women with polycystic ovary syndrome

The main dopamine metabolite, homovanillic acid (HVA), was measured in urine samples from 35 women with polycystic ovary syndrome (PCO) and in 38 normal menstruating women of the same age range. In both groups the plasma levels of LH, FSH, prolactin and testosterone were also measured. HVA excretion was significantly increased in women with PCO. Plasma levels of LH correlated negatively (r = -0.6268, 2a less than 0.001) to urinary HVA in the group of normal women. This correlation did not exist in the women with PCO. The results suggest that there is a disturbance of the inhibitory influence of dopamine on LH secretion in women with the syndrome, which is not due to a deficient synthesis or utilization of dopamine.

Dopamine might not be involved in the pathogenesis of polycystic ovary syndrome

The possible alteration in dopamine (DA) metabolism as an etiological factor was investigated in 31 normoprolactinemic patients with typical polycystic ovary syndrome (PCOS) in comparison with 14 normal women (early follicular phase). Subjects were submitted to intravenous infusion of 4 micrograms/kg DA per minute over a period of 3 hours and blood samples were collected every 30 minutes over a period of 5 hours. Two days later subjects were submitted to intravenous infusion of 10 mg metoclopramide (MCP) as a bolus and blood samples were collected every 15 minutes over a period of 2 hours. Dopamine infusion caused a similar maximum decrease (MD) in LH levels in both the PCOS and control groups (50.9% and 47.5%, respectively). No changes in plasma LH levels were observed in either group after MCP infusion. Dopamine caused a 50.2% and 60.4% MD in prolactin (PRL) in the PCOS and control groups, respectively, the difference being statistically non-significant. Metoclopramide increased PRL levels by 1261.0% and 1832.0% in the PCOS and control groups, respectively (not significant). In a double-blind study, the PCOS patients were treated with 5 mg/day bromocriptine (n = 16) or placebo (n = 15) over a period of 3 months and evaluated in clinical and laboratory terms during and after treatment. Seven patients in each group had monthly menstrual periods, but only 1 in each group had an ovulatory cycle (progesterone greater than 5 ng/ml). During treatment, median plasma PRL levels were significantly decreased only in bromocriptine-treated patients (10.8 vs 7.3 ng/ml). The present results lead us to question whether dopamine is indeed involved in the pathogenesis of normoprolactinemic PCOS and whether bromocriptine treatment is of benefit in this type of patients.

Evidence for a hypothalamic alteration of catecholamine metabolism in polycystic ovary syndrome

The role of brain catecholamine (CA) activity in the neuroendocrine regulation of the GnRH-LH system in polycystic ovary syndrome (PCO) was investigated by high-performance liquid chromatography (HPLC) with electrochemical detector. We measured urinary dopamine (DA), noradrenaline (NA), adrenaline (A), vanillylmandelic acid (VMA), homovanillic acid (HVA), 3,4-dihydroxyphenylacetic acid (DOPAC) and total 3-methoxy-4-hydroxyphenylglycol (MHPG) levels in a group of 12 women with PCO before and during peripheral dopa-decarboxylase blockade, by carbidopa. HVA and DOPAC concentrations were significantly lower (P less than 0.001 and P less than 0.005, respectively) in PCO patients compared with twelve control subjects in early follicular phase, whereas total MHPG concentrations and MHPG/VMA ratio were significantly higher (P less than 0.005) in PCO patients. Moreover, HVA and DOPAC concentrations in PCO patients were similar to those of the control subjects in preovulatory phase, while MHPG concentrations remained higher in PCO patients (P less than 0.01). DA, NA, A and VMA concentrations were similar to those of control subjects in both phases of the cycle. During carbidopa administration the concentrations of all urinary CAs and metabolites were unchanged, except those of DA which dropped markedly (P less than 0.001). These data suggest that (1) an altered central catecholamine metabolism consisting of DA deficiency and NA excess is present in PCO, and (2) the site of DA deficiency may be located in the hypothalamus.