Paeoniflorin ameliorates antipsychotic-induced hyperprolactinemia in rats by attenuating impairment of the dopamine D2 receptor and TGF-β1 signaling pathways in the hypothalamus and pituitary

ETHNOPHARMACOLOGICAL RELEVANCE

Paeoniflorin, a prominent component in some Chinese formulas for hyperprolactinemia-associated disorders, has been found to inhibit prolactin secretion in prolactinoma cells.

AIM

To examine the efficacy of paeoniflorin on hyperprolactinemia and the underlying mechanisms of action.

MATERIALS AND METHODS

Hyperprolactinemia in female rats was generated by administration of olanzapine (5 mg/kg, by a gavage method, once daily, × 13 weeks). The rats were co-treated with paeoniflorin (10 and 50 mg/kg). Prolactin and TGF-β1 concentrations were detected by ELISA. Protein expression was determined by Western blot. The effect in MMQ cells was also examined.

RESULTS

Paeoniflorin inhibited olanzapine-induced increases in plasma prolactin concentration and prolactin protein overexpression in the pituitary and hypothalamus of rats. Further, paeoniflorin restored olanzapine-induced downregulation of pituitary and hypothalamic dopamine D2 receptor (D2R) protein expression. More importantly, paeoniflorin attenuated olanzapine-suppressed protein expression of transforming growth factor (TGF)-β1 and its downstream genes, type II TGF-β receptor, type I TGF-β receptor and phosphorylated SMAD3 in the tissues. However, paeoniflorin did not affect plasma TGF-β1 concentration and hepatic TGF-β1 protein expression. In accord, olanzapine-induced increase in prolactin concentration, upregulation of prolactin protein expression, and downregulation of protein expression of the D2R and TGF-β1 signals in MMQ cells were attenuated.

CONCLUSIONS

This study demonstrates that paeoniflorin ameliorates olanzapine-induced hyperprolactinemia in rats by attenuating impairment of the D2R and TGF-β1 signaling pathways in the hypothalamus and pituitary. Our findings may provide evidence to support the use of paeoniflorin-contained Chinese herbs and formulas for hyperprolactinemia and its associated disorders.

The ancient Chinese formula Longdan Xiegan Tang improves antipsychotic-induced hyperprolactinemia by repairing the hypothalamic and pituitary TGF-β1 signaling in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Antipsychotics often induce hyperprolactinemia. The transforming growth factor (TGF)-beta1 signaling in the pituitary and hypothalamus inhibits prolactin synthesis and secretion, and its impairment is implicated in neuropsychiatric disorders. Longdan Xiegan Tang (LXT) alone or together with antipsychotics have been used to treat various neuropsychiatric diseases and hyperprolactinemia-associated disorders.

AIM OF THE STUDY

To investigate the effect of LXT on hyperprolactinemia and involvement of the TGF-beta1 signaling.

MATERIALS AND METHODS

Male rats were co-administered with olanzapine (5 mg/kg) and LXT extract (50 and 500 mg/kg) (p.o., × 8 weeks). Plasma concentrations of prolactin and TGF-beta1 were determined by ELISA. Protein expression was analyzed by Western blot.

RESULTS

Treatment of rats with LXT extract suppressed olanzapine-induced increase in plasma prolactin concentration and overexpression of pituitary and hypothalamic prolactin protein. Importantly, LXT restored olanzapine-induced decrease in protein expression of the key components of the TGF-beta1 signaling, TGF-beta1, type II TGF-beta receptor, type I TGF-beta receptor and phosphorylated SMAD3 in the pituitary and hypothalamus. Further, it antagonized downregulation of pituitary and hypothalamic dopamine D2 receptor (D2R) protein level, and inhibited pituitary estrogen receptor (ER) alpha and ERbeta protein expression.

CONCLUSIONS

The present results suggest that LXT ameliorates antipsychotic-induced hyperprolactinemia in rats by repairing the pituitary and hypothalamic TGF-beta1 signaling possibly via D2R, ERs or/and other pathways. Our findings may also provide scientific elucidation for use of the ancient Chinese formula to treat the impaired TGF-beta1 signaling-associated neuropsychiatric disorders.

DIAGNOSIS OF ENDOCRINE DISEASE: Primary empty sella: a comprehensive review

Primary empty sella (PES) is characterized by the herniation of the subarachnoid space within the sella, which is often associated with variable degrees of flattening of the pituitary gland in patients without previous pituitary pathologies. PES pathogenetic mechanisms are not well known but seem to be due to a sellar diaphragm incompetence, associated to the occurrence of upper sellar or pituitary factors, as intracranial hypertension and change of pituitary volume. As PES represents in a majority of cases, a neuroradiological findings without any clinical implication, the occurrence of endocrine, neurological and opthalmological symptoms, due to the above describes anatomical alteration, which delineates from the so called PES syndrome. Headache, irregular menses, overweight/obesity and visual disturbances compose the typical picture of PES syndrome and can be the manifestation of an intracranial hypertension, often associated with PES. Although hyperprolactinemia and growth hormone deficit represent the most common endocrine abnormalities, PES syndrome is characterized by heterogeneity both in clinical manifestation and hormonal alterations and can sometime reach severe extremes, as occurrence of papilledema, cerebrospinal fluid rhinorrhea and worsening of visual acuity. Consequently, a multidisciplinary approach, with the integration of endocrine, neurologic and ophthalmologic expertise, is strongly advocated and recommended for a properly diagnosis, management, treatment and follow-up of PES syndrome and all of the related abnormalities.

Giant prolactinomas in women

OBJECTIVE

To characterise distinctive clinical features of giant prolactinomas in women.

DESIGN

A multicentre, retrospective case series and literature review.

METHODS

We collected data from 15 female patients with a pituitary tumour larger than 4 cm and prolactin levels above 1000 μg/l and identified 19 similar cases from the literature; a gender-based comparison of the frequency and age distribution was obtained from a literature review.

RESULTS

The initial PubMed search using the term 'giant prolactinomas' identified 125 patients (13 women) responding to the inclusion criteria. The female:male ratio was 1:9. Another six female patients were found by extending the literature search, while our own series added 15 patients. The median age at diagnosis was 44 years in women compared with 35 years in men (P<0.05). All cases diagnosed before the age of 15 years were boys. In women (n=34), we observed a minor peak incidence during the third decade of life and a major peak during the fifth decade. Amenorrhoea was a constant feature with seven cases of primary amenorrhoea. In eight women with onset of secondary amenorrhoea before the age of 40 years, the diagnosis was made 2-31 years later (median 9 years) and in all but one because of tumour pressure symptoms. The prolactin levels were above 10,000 μg/l in 15/34 and misdiagnosis due to 'hook effect' occurred in two of them. Eighteen patients were treated with cabergoline; standard doses (<2.0 mg/week) were able to normalise prolactin in only 4/18 patients, and 7/18 patients were resistant to weekly doses ranging from 3.0 to 7.0 mg.

CONCLUSION

Giant prolactinomas are rare in women, often resistant to dopamine agonists and seem to be distributed in two age groups, with a larger late-onset peak.

Assessment of pre- and postoperative endocrine function in 94 patients with Rathke's cleft cyst

We reviewed 94 patients with Rathke's cleft cyst (RCC) who were surgically treated at Nippon Medical School Hospital between December 1995 and July 2009 to clarify the effect of surgery on their endocrine function. In our statistical analysis we considered their age and sex, the cyst volume, and preoperative MRI findings. Using simple linear- and multiple regression analysis we evaluated the association between these factors and their preoperative hormone baseline levels. To assess pre- and postoperative anterior pituitary function we subjected the results of various hormone loading tests to the Wilcoxon rank sum test. Surgery improved headache and visual impairment in most patients and elevated PRL levels were significantly normalized after surgery (p = 0.004). However, pre- and postoperative anterior pituitary hormone loading tests revealed that the levels of GH, TSH, LH, and FSH were not improved significantly by surgery. Although the ACTH loading test showed postoperative improvement, the change was not statistically significant. We suggest that RCC patients with headache or visual impairment are good candidates for surgery. We also recommend that patients with hyperprolactinemia and those with ACTH deficiency whose MRI findings reveal low-intensity on T1WI and high-intensity on T2WI are likely to benefit from surgery. In contrast, RCC patients with other hormone dysfunctions do not appear to benefit from surgical intervention.

A family with Camurati-Engelman disease. The role of the missense p.R218C mutation in TGFB1 in bones and endocrine glands

OBJECTIVES

Camurati-Engelmann disease (CED) is a rare form of progressive bone dysplasia due to mutations in the transforming factor gene TGFB1 on chromosome 19q13.1-q13.3. Endocrine complications such as osteoporosis, vitamin D deficiency, delayed puberty and hypogonadotrophic hypogonadism may be present.

METHODS AND RESULTS

Genetic analysis of the TGFB1 gene revealed a heterozygous missense mutation p.R218C in exon 4 of chromosome 19q13.1-q13.3 in a 14-year-old girl who presented with typical symptoms of CED, hyperprolactinaemia and menstrual irregularity. The patient responded well to prednisone 5 mg/kg per day as well as calcium and vitamin D supplements.

CONCLUSIONS

The role of p.R218C in TGFB1 on the mechanism of the disease itself and the complications of it in bones and endocrine glands remain unclear. Early recognition as well as a detailed understanding of the pathogenesis of the disease is important for future treatment options and better quality of life of such patients.

Strategies for the treatment of antipsychotic-induced sexual dysfunction and/or hyperprolactinemia among patients of the schizophrenia spectrum: a review

There is limited evidence for the management of sexual dysfunction and/or hyperprolactinemia resulting from use of antipsychotics in patients with schizophrenia and spectrum. The aim of this study was to review and describe the strategies for the treatment of antipsychotic-induced sexual dysfunctions and/or hyperprolactinemia. The research was carried out through Medline/PubMed, Cochrane, Lilacs, Embase, and PsycINFO, and it included open labels or randomized clinical trials. The authors found 31 studies: 25 open-label noncontrolled studies and 6 randomized controlled clinical trials. The randomized, double-blind controlled studies that were conducted with adjunctive treatment that showed improvement of sexual dysfunction and/or decrease of prolactin levels were sildenafil and aripiprazole. The medication selegiline and cyproheptadine did not improve sexual function. The switch to quetiapine was demonstrated in 2 randomized controlled studies: 1 showed improvement in the primary outcome and the other did not. This reviewed data have suggested that further well-designed randomized controlled trials are needed to provide evidence for the effects of different strategies to manage sexual dysfunction and/or hyperprolactinaemia resulting from antipsychotics. These trials are necessary in order to have a better compliance and reduce the distress among patients with schizophrenia.

Managing patients with antipsychotic drug-induced hyperprolactinaemia

This article outlines a range of interventions that mental health nurses can use in the management of patients with hyperprolactinaemia induced by antipsychotic medication. The article is aimed primarily at mental health nurse prescribers, but is relevant to all mental health nurses to inform their care of people at risk of developing an elevated prolactin level.

Quality of life in women with microprolactinoma treated with dopamine agonists

OBJECTIVES

To evaluate QOL in women with microprolactinomas treated with dopamine agonists, comparing the patients with normal versus those with elevated prolactin levels, and to identify clinical and biochemical influences on patients' QOL.

MATERIAL AND METHODS

A cross-sectional evaluation was performed in two University referral centers. Fifty women with microprolactinoma answered the SF-36 questionnaire by the time of their clinical evaluation. Their biochemical analysis included PRL, estradiol, testosterone, and SHBG. Fifty women of similar age distribution served as controls.

RESULTS

Patients had lower scores than controls in all SF-36 categories: physical functioning, physical role, pain, general health, vitality, social functioning, emotional aspect, and mental health. Within the patients' group, the ones with normal PRL levels had higher scores than those with high PRL levels in all categories but the physical role. The physical functioning score correlated with the free androgen index, while the pain, vitality, social functioning, emotional aspect, and mental health scores were associated with the prolactin levels obtained at study entry.

CONCLUSIONS

QOL is impaired in women with microprolactinoma treated with dopamine agonists, and was inversely associated with the PRL levels. This latter finding reinforces the importance of providing adequate disease control for these patients in order to avoid the adverse consequences of hyperprolactinemia on QOL.

Anti-nociceptive and anti-hyperprolactinemia activities of Fructus Viticis and its effective fractions and chemical constituents

Vitex rotundifolia L. is widely distributed along the sea coast of China. The aim of this study was to investigate the anti-nociceptive and anti-hyperprolactinemia activities of substances isolated from Fructus Viticis (the fruit of Vitex rotundifolia), which may be effective in the treatment of pre-menstrual symptoms, using acetic-acid-induced writhing and metoclopramide-dihydrochloride-induced hyperprolactinemia in mice. The fractions effective in terms of anti-nociceptive and anti-hyperprolactinemia activities were obtained from Fructus Viticis by elution through macro-porous resin, and polyamide and silica gel column chromatography. The standardization of the fractions obtained from the separation procedures was carried out by means of high-performance liquid chromatography (HPLC)-fingerprint. In this study, the flavone-enriched fraction (Fraction 6) showed a higher inhibitory rate than indomethacin (69.4% vs. 56.4%) at a dose of 50 mg/kg body wt., and significantly reduced the prolactin level as compared to HPRL-treated mice (8.2 ng/ml vs. 25.5 ng/ml). Furthermore, this fraction showed anti-nociceptive activity in a dose-dependent manner (10-50 mg/kg body wt., i.g.). On further purification with silica gel, Casticin was isolated from this fraction and it decreased abnormal serum levels of prolactin by approximately 50% (p < 0.01). Using bioassay-screening methods, our results indicate that the presence of flavonoids such as Casticin in this plant may be responsible for the activity effects. Casticin has potent analgesic and anti-hyperprolactinaemia properties, is likely to be one of the active components of Fructus Viticis, and may have a role in treating PMS (premenstrual syndrom).

The art and science of switching of antipsychotic medications, part 1

In the presentation "Prevalence of and Factors Influencing the Switching of Antipsychotic Medications," Weiden defines the recovery approach for the treatment of schizophrenia, focuses on reasons for switching antipsychotic medications, and offers recommendations for evaluating switch studies. In "Combining and Switching Medications in Bipolar Disorder," Young discusses the similarities and differences between schizophrenia and bipolar disorder, offers recommendations for switching medications in bipolar disorder, and evaluates studies of atypical antipsychotics in the treatment of bipolar disorder. Buckley's presentation, "Differential Pharmacology of Atypical Antipsychotics: Clinical Implications," examines response rates in patients with schizophrenia after switching antipsychotic medications, outlines receptor-binding profiles of atypical antipsychotics, highlights adverse events that may occur when switching antipsychotic medications, and offers recommendations for treating those adverse events.

Switching in the era of atypical antipsychotics. An updated review

The introduction of the newer atypical antipsychotic medications in the 1990s was the first major change in the psychopharmacologic treatment of schizophrenia in many years. Many patients previously treated with conventional antipsychotics showed marked improvement when switched to one of the newer agents. Yet the principles involved in switching patients to these agents initially posed a challenge for clinicians, with many patients becoming unstable and relapsing during switches. Now, a decade later, switching techniques are better understood, but, with atypical antipsychotics now the standard of care, new challenges have emerged. Surveys confirm a steady decrease in use of older antipsychotics and an increase in use of first-line atypical agents since 1994. Before the newer atypical agents, elective antipsychotic changes in "stable" outpatients were uncommon, but with more choices available, rates of switching, mostly from one atypical agent to another, are now 30%-50% a year in many outpatient clinics, a trend that is likely to continue with the expanding range of target symptoms and growing expectations for better outcomes. Whereas relapse prevention was once considered the primary goal, the focus has moved beyond stability towards recovery. This article focuses on recent developments in switching and highlights differences in the switching profiles of the most recently introduced antipsychotics, ziprasidone and aripiprazole, and compares their switching characteristics with those of the other first-line atypical antipsychotics.

Health monitoring for patients who have schizophrenia. Summary of the Mount Sinai Conference recommendations

Schizophrenia is associated with several chronic medical illnesses and a reduced life expectancy. This paper summarizes findings and recommendations from "The Mount Sinai Conference," held at the Mount Sinai School of Medicine in New York on October 17-18, 2002, and discusses the implications for improving medical monitoring of patients with schizophrenia who are managed in outpatient settings from the initiation of treatment. The Mount Sinai Conference involved a diverse panel of experts, including specialists on schizophrenia, obesity, diabetes, cardiology, endocrinology, and ophthalmology. Consensus recommendations included baseline measurement and regular monitoring of body mass index, blood glucose, lipid profiles, signs of prolactin elevation or sexual dysfunction, and movement disorders. Information from such measurements should be considered when selecting or switching antipsychotic agents and should trigger an evaluation of medication when abnormalities are detected.

Hyperprolactinaemia and antipsychotic therapy in schizophrenia

Prolactin is a polypeptide hormone that exists as a number of isoforms and is involved in a multitude of physiological processes. Prolactin secretion is promoted by various physiological stimuli and pathological processes and is inhibited by the action of dopamine on the lactotroph cells of the hypothalamus. Hyperprolactinaemia, an elevation of prolactin levels above the norm, is a physiological occurrence and is not of concern (including sexual dysfunction and decreased bone mineral density). Treatment of hyperprolactinaemia is usually confined to the removal of the primary cause of the disease, but several dopamine agonists have been investigated. Hyperprolactinaemia is also a side-effect of the conventional, and some of the second-generation, antipsychotics used in the treatment of schizophrenia. These agents rely on their dopamine antagonistic properties to provide their antipsychotic effects. However, this also removes the brake on prolactin secretion, leading to hyperprolactinaemia. While antipsychotic use has been linked to certain hyperprolactinaemia-related side-effects (sexual dysfunction), its link to others (decreased bone mineral density) has proved more controversial. The association of symptoms with antipsychotic use is further complicated by the fact that patients with schizophrenia can suffer from some of these symptoms because of the disease itself. In managing antipsychotic-induced hyperprolactinaemia, the initial step is to exclude other causes of hyperprolactinaemia while monitoring the occurrence of adverse effects. The physician should also engage in close consultation with the patient with regard to the benefits of the antipsychotic medication and the impact of any adverse effects. A regular risk-benefit discussion will allow the clinician to achieve optimal outcomes in each case.

Oestrogen effects in schizophrenia and their potential therapeutic implications--review

Increasing evidence from clinical as well as from epidemiological and basic research shows that oestrogens exert protective effects in schizophrenia. A brief overview of these protective effects will be provided, and potential therapeutic implications will be discussed. If these effects are confirmed, they could have important implications for prophylaxis and treatment. For instance, consideration would need to be given to oestrogen replacement in peri- and postmenopausal women with schizophrenia, adjunct oestrogen therapy in women with oestrogen deficiency syndromes, cycle-modulated neuroleptic therapy in women with frequent perimenstrual relapses, and/or emphasis on prolactin-sparing atypical neuroleptics in women with hypoestrogenism. Further research is urgently needed since there may be direct therapeutic benefits for women.

Effects of olanzapine on prolactin levels of female patients with schizophrenia treated with risperidone

BACKGROUND

This study was conducted to prospectively examine the effect of switching from risperidone to olanzapine on female schizophrenia patients who experienced menstrual disturbances, galactorrhea, and/or sexual dysfunction.

METHOD

Twenty female patients with DSM-IV schizophrenia who were taking risperidone and were suffering from menstrual disturbances, galactorrhea, and/or sexual dysfunction were enrolled. Patients were switched from risperidone to olanzapine over a 2-week period, then treated with olanzapine for 8 additional weeks. The serum prolactin concentrations were examined every 2 weeks. The Positive and Negative Syndrome Scale (PANSS), Abnormal Involuntary Movement Scale (AIMS), Simpson-Angus Scale for Extrapyramidal Symptoms (SAS), and questions from the Dickson-Glazer Sexual Functioning Scale were administered to evaluate efficacy, extrapyramidal side effects, and sexual and reproductive functioning at baseline and the endpoint of 10 weeks.

RESULTS

Serum prolactin levels decreased significantly (p < .01) following the switch from risperidone to olanzapine. Scores of PANSS, AIMS, and SAS at the endpoint were also significantly decreased (p < .01) compared to those of baseline. Patients experienced improvements in menstrual functioning and perceptions of sexual side effects.

CONCLUSION

Olanzapine reversed hyperprolactinemia in risperidone-treated female schizophrenic patients. This was associated with a decrease in amenorrhea, improved cycle regularity, and a decrease in sexual side effects that the women attributed to antipsychotic medication. This study suggests that switching to olanzapine is a safe and effective alternative method for patients with antipsychotic-induced hyperprolactinemia associated sexual and/or reproductive dysfunction. Long-term follow-up studies are warranted, with particular attention to the course of sexual and reproductive dysfunction.

Effects of dopamine d2 receptor agonists in a pituitary transplantation-induced hyperprolactinaemia/anovulation model in rats

1. In the present study, we investigated the effects of hyperprolactinaemia, induced by transplantation of anterior pituitary glands under the kidney capsule in female rats, on the relationship between serum and pituitary concentrations of the gonadotropins and on the oestrous cycle. 2. Rats with pituitary transplants showed increased serum prolactin concentrations and decreased serum concentrations of gonadotropins and increased pituitary concentrations of gonadotropins. Moreover, these rats showed persistent dioestrous and anovulation from 3 to 6 days after transplantation. 3. A single oral administration of cabergoline (at doses between 0.001 and 0.1 mg/kg) dose-dependently inhibited the elevated serum prolactin concentrations in hyperprolactinaemic rats. At 0.1 mg/kg, cabergoline induced a continuous reduction in serum prolactin concentrations for 5 days after administration. Terguride (0.1 mg/kg) and bromocriptine (10 mg/kg) also reduced serum prolactin concentrations at 1 and 3 days after administration. All three dopamine D2 receptor agonists increased serum gonadotropin concentrations and ovarian weight at 3 days after administration. 4. In rats exhibiting anovulation, a single oral administration of any one of the three dopamine D2 receptor agonists dose-dependently restored ovulation and a normal oestrous cycle appeared. Oral administration of cabergoline (0.03 mg/kg) or terguride (0.1 mg/kg) restored ovarian function and abolished the anovulation following a reduction in serum prolactin concentrations. However, bromocriptine (10 mg/kg) did not completely abolish anovulation. Following administration of terguride (0.3 mg/kg) or bromocriptine (30 mg/kg), only one normal oestrous cycle appeared; however, following cabergoline (0.1 mg/kg), two normal oestrous cycles appeared. 5. These results suggest that cabergoline has a potent and long-lasting action as a dopamine D2 receptor agonist and, thus, should be a useful drug for the treatment of galactorrhoea and hyperprolactinaemic amenorrhoea and/or anovulation in humans.

Hormonal side effects in women: typical versus atypical antipsychotic treatment

Neuroleptic-induced hyperprolactinemia can cause menstrual disorders, impaired fertility, galactorrhea, and sexual dysfunction, as well as hypoestrogenism secondary to disruption of the hypothalamic-pituitary-ovarian axis. The development of the prolactin-sparing atypical antipsychotic drugs offers prevention and resolution of these adverse reactions. Thus far, this property of the new medications has received insufficient clinical attention. The authors use case vignettes to discuss assessment and management of clinical situations that arise as a result of antipsychotic-induced endocrine changes.

Some adverse effects of antipsychotics: prevention and treatment

Antipsychotic medication causes a wide range of adverse effects, which can be serious and may further imperil both the physical and psychological health of schizophrenic patients. The range of side effects patients commonly encounter includes weight gain, endocrine disturbances, sedation, anticholinergic effects, hypotension, seizures, and extrapyramidal symptoms. Less common and unpredictable reactions are blood dyscrasias, cardiotoxicity, sudden death, and the neuroleptic malignant syndrome. Antipsychotic drugs differ significantly regarding their propensity to cause these reactions. Patients should undergo comprehensive health checks before an antipsychotic is prescribed, and drug therapy should be individualized to take account of any preexisting symptoms. Side effects and the wider implications of drug treatment, such as effects on occupational and social functioning, should be discussed with the patient before initiating therapy. Patients should be regularly monitored for side effects during treatment and switched to alternative therapy if side effects are serious and/or persistent.

Surgery combined with dopamine agonists versus dopamine agonists alone in long-term treatment of macroprolactinoma: a retrospective study

We retrospectively analysed the long-term treatment results (median 8 years) of 31 patients with macroprolactinoma. 17 patients were treated by pituitary surgery (group 1) followed by long-term dopamine agonist therapy whereas 14 patients received long-term dopamine agonist therapy alone (group 2). 2 patients of group 1 and 1 patient of group 2 had external pituitary irradiation because of progressive disease. The two groups were comparable with respect to age, gender and initial prolactin (PRL) levels. At the end of the observation period dopamine agonist dosage could be reduced by 50% in group 1 and by 39.3% in group 2. Pituitary function did not change substantially during therapy. Complete remissions (no visible tumour in CT or MRI, normal PRL levels under current dopamine agonist medication) were achieved in 23.5% of group 1 vs. 21.4% of group 2, partial remissions (reduction of PRL and tumour size) in 35.3% vs. 64.3%, stable disease in 23.5% vs. 7.1% and progressive disease in 17.7% vs. 7.1% (differences not significant). Visual field defects showed 28.4% remissions (complete and partial) in group 1 versus 50% in group 2. Dopamine agonist therapy could be stopped definitively in only 1 patient of group 2 with an invasive macroprolactinoma. Initial surgical reduction of tumour load followed by medical therapy does not seem to guarantee a better long-term outcome than dopamine agonist therapy alone if the patient responds to and tolerates dopamine agonist therapy. Surgery should be reserved for non-responders, drug-intolerant or non-compliant patients, and for those with acute severe neurological compromise.

Hypothalamo-pituitary effects of RU486: inhibition of progesterone-induced hyperprolactinaemia

Monkeys given oestrogen priming at physiological levels for at least 1 week become hyperprolactinaemic upon the addition of physiological progesterone administration. Here, using RU486, we test whether that this oestrogen/progestin-induced hyperprolactinaemia results from classical progesterone actions at the hypothalamo-pituitary level. Blood samples were collected daily from study day 1-67. Each monkey (n = 2) received daily injections of 25 micrograms/kg oestradiol benzoate, i.m., on study days 5-60. Progesterone-filled silastic capsules (3 cm) were inserted on study day 14 and removed on day 53. On study days 39-45, each monkey received RU486 (25 mg/day, p.o.). Serum samples were stored at -20 degrees C until assayed for prolactin, oestradiol, progesterone and RU486 by radioimmunoassay. Hyperprolactinaemia was induced in all three monkeys upon insertion of progesterone capsules. Prolactin concentrations fell sharply during RU486 treatment to nadirs some 10-fold less than prior to RU486 treatment. The time series was modelled by the Box-Jenkins autoregressive-integrated moving average (ARIMA) method with progesterone producing a gradual increase in prolactin concentrations and RU486 producing a sudden decrease. Statistically significant effects of progesterone and RU486 were found. Thus, the addition of progesterone to an oestrogenized milieu significantly increased prolactin concentrations, and RU486 fully reversed this effect. This evidence indicates that the progesterone-induced hyperprolactinemia in an oestrogenized milieu results from classical progesterone effects.

Acute administration of bromocriptine abolishes the hyperprolactinemic response induced by submaximal exercise in man

The effective control of hypophysial prolactin (PRL) secretion with a pharmacological agent is a prerequisite for the investigation of the role of hyperprolactinemia observed during exercise. Using bromocriptine, a potent inhibitor of PRL secretion, this study established the proper experimental conditions whereby any significant increase in plasma PRL level can be prevented and basal circulating levels maintained during physical exercise. On three occasions at weekly intervals, 15 male adults, separated into two groups, exercised on an ergocycle (40 min at 65% VO2max) either 1 or 3 h after ingesting either placebo or 1.25 or 2.50 mg of bromocriptine mesylate (Parlodel; Sandoz Canada Inc., Dorval, Qué.). Under all conditions, the plasma PRL elevation observed during exercise after placebo was prevented by the administration of bromocriptine. Resting plasma PRL levels were maintained when exercise was performed 1 h after bromocriptine ingestion, but were significantly reduced when exercise was performed 3 h after administration of either bromocriptine dosages. Considering the primary and secondary effects observed, 1.25 mg of bromocriptine administered 1 h before exercise provides suitable experimental conditions to investigate the role of the increase in plasma PRL during physical exercise.

[Effect of long-term treatment with prazosin and its combination with nadolol on the levels of blood hormones of the hypophyseal- gonadal system in patients with hypertension]

The levels of pituitary and gonadal hormones were measured by radioimmunoassay during a long-term (12-month) therapy with prazosin and its combination in 23 patients aged 30-59 years who suffered from Stage II hypertensive disease. Prazosin monotherapy resulted in a significant decrease in prolactin levels, followed by inhibited elaboration of luteinizing, follicle-stimulating, and testicular hormones in the first 6 months of therapy without changing estradiol levels. The hypoprolactinemic effect of prazosin was significantly enhanced with an increase in therapy duration and more profound in patients who had high baseline prolactin levels and in younger patients. Prazosin in combination with nadolol was found to level off the hyperprolactinemic effect of the latter without potentiating the reduction in the levels of follicle-stimulating, luteinizing, and testicular hormones which was observed during therapy with each drug alone.

A comparison of the transient hyperprolactinaemic stress response obtained using two different methods of analgesia for ultrasound-guided transvaginal oocyte retrieval

Transient hyperprolactinaemia has been shown to accompany the procedure of oocyte retrieval under laparoscopic control. This study was concerned with establishing whether transvaginal oocyte retrieval was also associated with hyperprolactinaemia and whether the hyperprolactinaemic response was dependent on the method of anaesthesia/analgesia employed. Two distinct patterns were recorded. Oocyte retrieval under general anaesthesia was accompanied by a rapid rise in prolactin levels, which peaked after 40 min. Oocyte retrieval under intravenous sedation was associated with a slow rise in circulating prolactin concentrations. Significant differences in the prolactin rise between the general anaesthesia and sedation groups appeared within 10 min of the start of the procedure. It is concluded that although the surgical stress of oocyte recovery is associated with mild transient hyperprolactinaemia, most of the hyperprolactinaemic response is due to the anaesthetic.

Idazoxan inhibits hyperprolactinaemia in ovariectomized estrogen-treated rats

The alpha 2-antagonist idazoxan (IDZ) has previously been shown to inhibit hyperprolactinaemia triggered by various stimuli such as lactation, stress, serotonergic agents and morphine (Preziosi, Martire, Navarra, Pistritto and Vacca 1989; Krulich, Jurcovicova and Le 1989). In this study, we investigated the PRL-lowering activity of IDZ in ovariectomized estrogen-treated (OET) rats; since a PRL surge usually occurs in normal cycling rats on the day of proestrus, the effect of IDZ on pulsatile PRL release in intact female rats was also studied. IDZ significantly lowered plasma PRL levels in OET rats; no elevated PRL values were observed in normal cycling rats, indicating that IDZ might inhibit PRL surges in these animals. It is concluded that IDZ is an effective PRL-lowering agent in a number of physiological and pharmacological hyperprolactinaemic models.

Bromocriptine inhibition of anesthesia-induced hyperprolactinemia: effect on serum and follicular fluid hormones, oocyte fertilization, and embryo cleavage rates during in vitro fertilization

Thirty-two patients undergoing in vitro fertilization (IVF) were given bromocriptine either 1 or 12 hours before anesthesia or received no drug to determine what effect suppression of transient, anesthesia-induced hyperprolactinemia would have on peripheral and follicular fluid hormones, fertilization and cleavage rates, and pregnancy. Thirty minutes after anesthesia, there was a 120-ng/mL rise in serum prolactin (PRL) in control patients versus an insignificant change in women given bromocriptine. Levels of PRL in follicular fluid were significantly less, and estradiol (E2) levels were higher (P less than 0.05) in all bromocriptine-treated patients compared with controls, whereas follicular fluid levels of progesterone (P), inhibin activity, and midluteal serum P were unaffected. Although fertilization and pregnancy rates were similar, a greater proportion of fertilized oocytes from bromocriptine-treated patients advanced to cleaving embryos compared with controls (95% versus 63%, respectively; P less than 0.001). We conclude that bromocriptine, given before anesthesia, can suppress transient, anesthesia-induced hyperprolactinemia and dramatically alter follicular fluid concentrations of PRL and E2. Although these changes in hormonal milieu affected neither oocyte fertilization nor pregnancy rate in our IVF patients, they seemed to have a positive influence on embryonic development after IVF.

Normalization of serum prolactin levels in hemodialysis patients on recombinant human erythropoietin

Correction of anemia in long-term hemodialysis patients by recombinant human erythropoietin (r-HuEPO) has been reported to improve sexual function. As elevated serum prolactin levels are believed to contribute to altered sexual function in uremia, we followed serum prolactin and testosterone levels during four months of r-HuEPO therapy. Within these four months, hematocrit values rose from 23.7 +/- 1.2 to 35.7 +/- 0.2% and hemoglobin from 7.3 +/- 0.3 to 11.3 +/- 0.4 g/100 ml. In parallel, serum prolactin values decreased significantly, from 66.9 +/- 9.3 to 9.6 +/- 2.6 ng/ml in females and from 39.5 +/- 10.5 to 10.3 +/- 1.0 ng/ml in male dialysis patients. Testosterone concentrations were in the lower normal range in male patients and remained unchanged during r-HuEPO therapy. Sexual function improved in four out of seven males, and five out of nine female patients started to have regular menstruations again. It appears that treatment of anemia in end-stage renal disease by r-HuEPO may improve sexual function by lowering elevated serum prolactin concentrations.

D-Trp6-luteinizing hormone-releasing hormone inhibits sulpiride-induced hyperprolactinemia in normal men

The effect of a potent agonistic analog of LHRH, D-Trp6-LHRH, on hyperprolactinemia induced by sulpiride was studied in normal men. Six men received sulpiride (100 mg, twice daily, orally) for 44 days. D-Trp6-LHRH was given sc during the last 2 weeks of sulpiride administration; the dose was 500 micrograms on the first day and 100 micrograms daily for the subsequent 14 days. All men had high serum PRL levels before D-Trp6-LHRH administration (mean +/- SEM, 56 +/- 9 ng/mL), which decreased significantly after the first dose of the analog (45 +/- 5 ng/mL; P = 0.031) and also after 15 days of analog administration (41 +/- 6 ng/mL; P = 0.016). These data demonstrate that administration of LHRH agonist can inhibit the hyperprolactinemic effect of sulpiride, suggesting a direct action of the analog on the pituitary gland to modulate PRL secretion.

Bromocriptine inhibition of hyperprolactinemia during surgery

The material included two groups of 10 women undergoing diagnostic laparoscopy. General anesthesia was administered by injection of 0.1 mg fentanyl followed by infusion of propanidide-succinylcholine. The control group received no medication prior to surgery, whereas patients in the experimental group were given 5 mg bromocriptine per os. Blood samples for prolactin determinations were drawn as the patients were placed on the operating table and immediately following surgery. The association of anesthesia and surgery caused prolactin levels to rise from 10.9 +/- 3.5 to 168 +/- 18.7 ng . ml-1 in the control group (p much less than 0.001) and from 3.5 +/- 0.5 to 7.5 +/- 1.1 ng . ml-1 in the test group (p less than 0.001). A significant difference was noted between the two groups for their pre- and postoperative levels and prolactin response (p less than 0.05, p much less than 0.001 and p much less than 0.001, respectively). The proposed protocol successfully suppresses prolactin increase during surgery and constitutes a useful tool for investigating hyperprolactinemia and its consequences during this same time. Possible applications include in vitro fertilization and studies on prolactin receptor-bearing tumors.