Protective effect of exogenous melatonin on testicular histopathology and histomorphometry of adult rats with domperidone-induced hyperprolactinemia.

Hyperprolactinemia is a pathological condition resulting from increased prolactin that directly affects reproduction, as this condition inhibits the release of LH, FSH and gonadal steroidogenesis, bringing several negative clinical associations in reproduction. In contrast, melatonin (MEL) plays an important role in the regulation of steroidogenesis and modulates damages to the process of spermatogenesis. The objective was to analyze the protective effects of exogenous melatonin on the testis of hyperprolactinemic adult rats. Forty-eight male rats were used, divided into two treatment periods: 30 and 60 days, each treatment was subdivided into three groups: Control, Hyper (hyperprolactinemia), and Hyper+MEL (hyperprolactinemia and melatonin). Treatment with melatonin was 200 µg/100 g, subcutaneously. Induction of hyperprolactinemia was obtained with a dose of 4 mg/kg of domperidone, subcutaneously. The results of the histopathology demonstrated that the animals in the Hyper group presented degeneration of germ cells when compared to the control. In addition, the degenerations were presented in smaller quantities in the Hyper+MEL, in both treatment periods, evidencing the benefits of the melatonin in gonadal regeneration. The Hyper group of both treatment periods showed a decrease in tubular diameter, epithelium height, and tubular area, in addition to a decrease in Sertoli cells, when compared to the control and the Hyper+MEL group. In conclusion, the hyperprolactinemia can affect the germinal epithelium and testicular microstructure; the exogenous melatonin has a protective effect against hyperprolactinemia, reducing testicular damage.

Severe Hyperprolactinemia Promotes Brown Adipose Tissue Whitening and Aggravates High Fat Diet Induced Metabolic Imbalance.

Background: The association of high serum prolactin and increased body weight is positive but controversial, therefore we hypothesized that additional factors such as diets and the impact of prolactin on brown adipose tissue may condition its metabolic effects. Methods: We used LacDrd2KO females with lifelong severe hyperprolactinemia due dopamine-D2 receptor deletion from lactotropes, and slow onset of metabolic disturbances, and compared them to their respective controls (Drd2 loxP/loxP ). Food intake, and binge eating was evaluated. We then challenged mice with a High Fat (HFD) or a Control Diet (CD) for 8 weeks, beginning at 3 months of age, when no differences in body weight are found between genotypes. At the end of the protocol brown and white adipose tissues were weighed, and thermogenic and lipogenic markers studied, using real time PCR (Ucp1, Cidea, Pgc1a, Lpl, adiponectin, Prlr) or immunohistochemistry (UCP1). Histochemical analysis of brown adipose tissue, and glucose tolerance tests were performed. Results: Hyperprolactinemic mice had increased food intake and binge eating behavior. Metabolic effects induced by a HFD were exacerbated in lacDrd2KO mice. Hyperprolactinemia aggravated HFD-induced body weight gain and glucose intolerance. In brown adipose tissue pronounced cellular whitening as well as decreased expression of the thermogenic markers Ucp1 and Pgc1a were observed in response to high prolactin levels, regardless of the diet, and furthermore, hyperprolactinemia potentiated the decrease in Cidea mRNA expression induced by HFD. In subcutaneous white adipose tissue hyperprolactinemia synergistically increased tissue weight, while decreasing Prlr, Adiponectin and Lpl mRNA levels regardless of the diet. Conclusions: Pathological hyperprolactinemia has a strong impact in brown adipose tissue, lowering thermogenic markers and evoking tissue whitening. Furthermore, it modifies lipogenic markers in subcutaneous white adipose, and aggravates HFD-induced glucose intolerance and Cidea decrease. Therefore, severe high prolactin levels may target BAT function, and furthermore represent an adjuvant player in the development of obesity induced by high fat diets.

Saponin-rich extract of Tribulus terrestris alleviates systemic inflammation and insulin resistance in dietary obese female rats: Impact on adipokine/hormonal disturbances.

Tribulus terrestris saponins (TTS) have been longley used as an overall tonic and recent studies showed they influence inflammatory conditions. We examined the ameliorative effect of a commercial formula of a saponin-rich extract of TT in a model of dietary obesity in female rats focusing on their ability to control the inflammatory burden, insulin resistance (IR), adipokine expression and the related reproductive system pathologies. Female rats were fed with high fat diet (HFD) for 14 weeks to launch diet-induced obesity; they were assigned as: the obese control female rats (OFR) which received no treatment and TTS (5 and 10 mg/kg/day) treated rats; they were compared to a normal rat group. We determined the IR index, serum/tissue inflammatory cytokines, and adipose tissue adipokine expression and examined the secondary ovarian pathologies. Body weight gain, serum triglycerides and IR (>5-fold) in the OFR group were greater than the normal group; TTS lessened these parameters compared with the OFR group. TTS, at 10 mg/kg dose, ameliorated mRNA expression of leptin and visfatin genes in addition to serum inflammatory cytokine levels. Moreover, TTS corrected the hyperprolactinemia and other hormonal disturbances and ameliorated the ovarian pathologies. This study highlighted that the anti-inflammatory properties of TTS helped in alleviation of IR and body weight gain in OFR. Upon correction of obesity manifestations, the gonadal hormone dysregulations and ovarian pathologies were subsequently ameliorated. We can consider TTS as a promising candidate that may alleviate the inflammatory burden, IR and adipokine expression in obesity and hence prevent the secondary gonadal complications in female subjects if appropriate clinical studies are available.

Persistent bone impairment despite long-term control of hyperprolactinemia and hypogonadism in men and women with prolactinomas.

While prolactinoma patients have high bone turnover, current data are inconclusive when it comes to determining whether correction of hyperprolactinemia and associated hypogandism improves osteodensitometric data in men and women over the long term. In a large cohort of including 40 men and 60 women, we studied the long-term impact of prolactinoma treatment on bone mineral density (BMD) in men versus women, assessed adverse effects of a primary surgical or medical approach, and evaluated data for risk factors for impaired BMD at last follow-up using multivariate regression analyses. Median duration of follow-up was 79 months (range 13-408 months). Our data indicate that the prevalence of impaired BMD remained significantly higher in men (37%) than in women (7%, p < 0.001), despite the fact that hyperprolactinemia and hypogonadism are under control in the majority of men. We found that persistent hyperprolactinemia and male sex were independent risk factors for long-term bone impairment. Currently, osteoporosis prevention and treatment focus primarily on women, yet special attention to bone loss in men with prolactinomas is advised. Bone impairment as "end organ" reflects the full range of the disease and could become a surrogate marker for the severity of long-lasting hyperprolactinemia and associated hypogonadism.

Ectopic hyperprolactinaemia due to a malignant uterine tumor resembling ovarian sex cord tumors (UTROCST).

PURPOSE: Moderate hyperprolactinaemia (2-5 times upper limit of normal) occurring in a patient with a normal pituitary MRI is generally considered to be due to a lesion below the level of detection of the MRI scanner assuming macroprolactin and stress have been excluded. Most patients with mild-to-moderate hyperprolactinaemia and a normal MRI respond to dopamine agonist therapy. We present the rare case of a patient who had prolactin elevation typical of a prolactin-secreting pituitary macroadenoma,with a normal cranial MRI, and in whom the prolactin rose further with dopamine agonist treatment. Subsequent investigations revealed ectopic hyperprolactinaemia to a uterine tumor resembling ovarian sex cord tumor (UTROSCT) which resolved following tumor resection. Although mostly considered to be benign, the UTROSCT recurred with recurrent hyperprolactinaemia and intraabdominal metastases. METHODS: We have systematically and critically reviewed existing literature relating to ectopic hyperprolactinaemia in general and UTROCST specifically. RESULTS: Fewer than 80 cases of UTROSCTs have been reported globally of which about 23% have shown malignant behaviour. There are fewer than 10 cases of paraneoplastic hyperprolactinaemia originating from uterine neoplasms including one other case of ectopic hyperprolactinaemia to a UTROSCT. CONCLUSIONS: Our case demonstrates the importance of screening for extracranial hyperprolactinaemia in the context of: (1) substantially raised prolactin (10× ULN) and (2) normal cranial MRI assuming macroprolactin has been excluded. The majority of extracranial ectopic prolactin-secreting tumors occur in the reproductive organs.

Hyperprolactinemia in Acromegaly is Related to Prolactin Secretion by Somatolactotroph Tumours.

The aim of this study is to assess differences in patient characteristics, tumour characteristics and hormone levels between acromegalic patients with and without hyperprolactinemia. 44 patients of the University Hospital of Brussels, Belgium with acromegaly who were diagnosed between January 2007 and July 2018 were included in this study. Nineteen patients were classified in the hyperprolactinemia group and 25 patients were classified in the normoprolactinemia group. No significant differences between acromegalic patients with and without hyperprolactinemia were found in age at diagnosis, gender, presence of hyperprolactinemia symptoms, insulin-like growth factor 1, growth hormone and testosterone levels, tumour volume, tumour invasiveness, immunohistochemistry of growth hormone and prolactin, Ki-67 index and mitotic index. However, for a cut-off of 10% of prolactin-positive cells, there was a trend towards a higher percentage of prolactin-positive tumours in hyperprolactinemia patients (p=0.054) and higher mean prolactin level in case of positive prolactin immunostaining (p=0.007)). In our study there were no differences in characteristics between acromegaly patients with hyper- and normoprolactinemia. An association between the serum prolactin level and the positivity of prolactin immunohistochemistry of the adenoma tissue was found. The absence of a difference in tumour volume between patients with hyper- and normoprolactinemia suggests that the hyperprolactinemia is likely to be caused by the co-secretion of growth hormone and prolactin by the tumour. Finally, for the first time, the cut-off of 10% of prolactin cells was validated for the diagnosis of somatolactotroph tumours in acromegaly.

Cardiac valvular abnormalities associated with use and cumulative exposure of cabergoline for hyperprolactinemia: the CATCH study.

BACKGROUND: Whether lower dose cabergoline therapy for hyperprolactinemia increases risk of valvular dysfunction remains controversial. We examined valvular abnormalities among asymptomatic adults with hyperprolactinemia treated with dopamine agonists. METHODS: This cross-sectional study was conducted among adults receiving cabergoline or bromocriptine for > 12 months for hyperprolactinemia and had no cardiac-related symptoms. Cardiac valve morphology and function were assessed from transthoracic echocardiograms at the study visit (except for two participants) with evaluation performed blinded to type and duration of dopamine agonist received. RESULTS: Among 174 participants (mean age 49 ± 13 years, 63% women) without known structural heart disease before starting therapy, 62 received only cabergoline, 63 received only bromocriptine, and 49 received both. Median cabergoline use was 2.8 years in cabergoline only users and 3.2 years for those exposed to both cabergoline and bromocriptine; median bromocriptine use was 5.5 years in bromocriptine only users and 1.1 years for those exposed to both cabergoline and bromocriptine. Compared with bromocriptine only users (17.5%), regurgitation of ≥1 valve was more common for cabergoline only (37.1%, P = 0.02) but not for combined exposure (26.5%, P = 0.26). Compared with bromocriptine only exposure (1.6%), regurgitation of ≥2 valves was more common for cabergoline only (11.3%, P = 0.03) and combined exposure (12.2%, P = 0.04). Cabergoline only users had higher age-sex-adjusted odds for ≥1 valve with grade 2+ regurgitation compared to bromocriptine only users (adjusted odds ratio [aOR] 3.2, 95% confidence interval [CI]:1.3-7.5, P = 0.008), but the association for combined exposure to cabergoline and bromocriptine was not significant (aOR 1.7, 95%CI:0.7-4.3, P = 0.26). Compared to bromocriptine only, age-sex-adjusted odds of ≥2 valves with grade 2+ regurgitation were higher for both cabergoline only (aOR 8.4, 95% CI:1.0-72.2, P = 0.05) and combined exposure (aOR 8.8, 95% CI:1.0-75.8, P = 0.05). Cumulative cabergoline exposure > 115 mg was associated with a higher age-sex adjusted odds of ≥2 valves with grade 2+ regurgitation (aOR 9.6, 95%CI:1.1-81.3, P = 0.04) compared to bromocriptine only. CONCLUSIONS: Among community-based adults treated for hyperprolactinemia, cabergoline use and greater cumulative cabergoline exposure were associated with a higher prevalence of primarily mild valvular regurgitation compared with bromocriptine. Research is needed to clarify which patients treated with dopamine agonists may benefit from echocardiographic screening and surveillance.

Impulse Control Disorders in Dopamine Agonist-Treated Hyperprolactinemia: Prevalence and Risk Factors.

CONTEXT: There are growing reports of dopamine agonist (DA)-induced impulse control disorders (ICDs) in hyperprolactinemic patients. However, the magnitude of this risk and predictive factors remain uncertain. OBJECTIVE: To determine ICD prevalence and risk factors in DA-treated hyperprolactinemic patients compared to community controls. DESIGN, SETTING AND PARTICIPANTS: Multicenter cross-sectional analysis of 113 patients and 99 healthy controls. MAIN OUTCOME MEASURES: Participants completed a neuropsychological questionnaire consisting of the Depression Anxiety Stress Scale (DASS21), Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease (QUIP-S), Hypersexual Behavior Inventory (HBI), Hypersexual Behavior Consequences Scale and Social Desirability Response Set Scale. Demographic and clinical data were collated to determine ICD risk factors. Patients testing positive for an ICD were offered a semistructured psychological interview. RESULTS: Patients were more likely than controls to test positive by QUIP-S for any ICD (61.1 vs 42.4%, P = .01), hypersexuality (22.1 vs 8.1%, P = .009), compulsive buying (15.9 vs 6.1%, P = .041) and punding (18.6 vs 6.1%, P = 0.012), and by HBI for hypersexuality (8.0 vs 0.0%, P = 0.004). Independent risk factors were male sex (odds ratio [OR] 13.85), eugonadism (OR 7.85), Hardy's tumor score and psychiatric comorbidity (OR 6.86) for hypersexuality, and age (OR 0.95) for compulsive buying. DASS21 subset scores were higher in patients vs controls and in patients with vs without different ICDs. Only 19/51 (37.3%) interviewed patients were aware of the relationship between DAs and ICDs before the study. CONCLUSIONS: DA therapy poses a high, previously underestimated risk of ICDs, especially in the form of hypersexuality in eugonadal men.

A Brazilian multicentre study evaluating pregnancies induced by cabergoline in patients harboring prolactinomas.

OBJECTIVE: To evaluate the maternal-fetal outcomes of CAB-induced pregnancies in patients with prolactinoma in a large cohort. METHODS: The prevalence of tumor growth, miscarriage, preterm, low birth weight, congenital malformations and impairment in neuropsychological development in children among women treated with CAB were assessed in a Brazilian multicentre retrospective observational study, RESULTS: We included 194 women with a mean age of 31 (17-45) years, 43.6% presenting microadenomas and 56.4% macroadenomas, at prolactinoma diagnosis. In 233 pregnancies, CAB was withdrawn in 89%, after pregnancy confirmation. Symptoms related to tumor growth occurred in 25 cases, more frequently in macroadenomas. The overall miscarriage rate was 11%, although higher in the subgroup of patients with CAB maintainance after pregnancy confirmation (38% vs. 7.5%). Amongst the live-birth deliveries, preterm occurred in 12%, low birth weight in 6% and congenital malformations in 4.3%. Neuropsychological development impairment was reported in 7% of cases. CONCLUSIONS: Our findings confirm previous results of safety in maternal and fetal outcomes in CAB-induced pregnancies; nevertheless, CAB maintenance after pregnancy confirmation was associated with higher miscarriage rate; result that must be further confirmed.

Serum Prolactin Contributes to Enhancing Prolactin Receptor and pJAK2 in Type I Endometrial Cancer Cells in Young Women Without Insulin Resistance.

Elevated levels of serum prolactin and a high expression of prolactin receptor (PRLR) in cancer cells was recently identified in patients with endometrial cancer (EC). However, the impact of prolactin on EC remains unknown. The aim of this study was to elucidate the clinical and immunohistochemical characteristics of hyperprolactinemic patients with EC according to the pathogenetic types, type I and type II. EC patients were retrospectively divided into a high prolactin (HP) group and a low prolactin (LP) group by a serum prolactin level of 20 ng/mL and were compared between 2 groups. The expression of PRLR, phosphorylated Janus-kinase 2 (pJAK2), estrogen receptor-α, progesterone receptor, and PTEN in cancer tissue were evaluated by immunohistochemistry. Ninety-nine patients were identified. In the type I group, HP group was significantly younger (45.2 vs. 52.2, P=0.028) and their insulin resistance was significantly lower (1.6 vs. 2.5, P=0.033) than those in LP group, and the expression of PRLR and pJAK2 in the HP group was significantly higher than that in the LP group (immunoreactive score: 6.8 vs. 3.9, P=0.003; 5.7 vs. 2.6, P<0.001, respectively). In the type 2 group, there were no differences between all the term. In the type I group, the rate of loss of PTEN in the HP group was significantly lower than the LP group (25.0% vs. 60.7%, P=0.024). Prolactin-PRLR signaling may play a crucial role for the progression of type I EC without involving the PTEN mutation in young hyperprolactinemic women without insulin resistance.

Galactocele of adult male breast: A cytopathologist's perspective.

Galactocele, although a common cytological diagnosis in females, is not previously reported as a cause of breast enlargement in adult males. Hyperprolactinemia is the principal cause of galactocele in male breast. Besides drug induced hyperprolactinemia, other anatomical lesions of hypothalamo-pituitary region and different medical conditions like cirrhosis and chronic kidney disease are to be considered along with a full evaluation of features revealing hypogonadism in case of galactocele. Aspirated milk from the male breast is the primary clue for this detailed investigation process. Here we are presenting the first case of galactocele of the male breast due to hypogonadotropic hypogonadism with idiopathic hyperprolactinemia.

Clinical Consultation Guide on Imaging in Male Infertility and Sexual dysfunction.

Imaging can benefit clinicians in evaluating men with infertility or sexual dysfunction by giving an overview of a patient's overall clinical condition before undertaking an invasive procedure. An understanding of the limitations and advantages of image modalities used in clinical practice will ensure that clinicians can optimize patient care with imaging when necessary. PATIENT SUMMARY: The objective of this article was to review the current literature on imaging modalities used for the diagnosis and management of male infertility and sexual dysfunction. An understanding of the advantages and limitations of these imaging modalities will ensure that clinicians can optimize patient care with imaging when necessary.

Cabergoline for the treatment of bromocriptine-resistant invasive giant prolactinomas.

PURPOSE: Few studies have specifically focused on the effect of cabergoline on invasive giant prolactinomas (IGPs) resistant to bromocriptine. This study aims to evaluate whether cabergoline could be used as an effective therapy for patients with bromocriptine-resistant IGPs. METHODS: This retrospective study included 15 patients with bromocriptine-resistant IGPs who received treatment at our department during 2007-2015. Cabergoline was administered in all 15 patients, with the dose adjusted depending on the prolactin response of each patient. Parameters for outcome assessment included prolactin level, pituitary function, tumor size, improvement of the clinical symptoms, visual field defects, drug tolerance, and disease recurrence. RESULTS: Cabergoline was effective for the treatment of the patients with bromocriptine -resistant IGPs as represented by normalization of the prolactin level in 12/15 patients; improvement or normalization of the pituitary function in 4/5 patients with hypopituitarism; significant reduction in tumor size in 14/15 patients; and relief of the clinical symptoms in 11/15 patients. All 15 patients showed good tolerance to cabergoline. In addition, no recurrence was observed during the mean follow-up period of 63.47 (range 30-145) months. CONCLUSIONS: Data of this retrospective study demonstrate that cabergoline is an excellent option for the treatment of patients with bromocriptine-resistant IGPs.

Hyperprolactinemia-inducing antipsychotics increase breast cancer risk by activating JAK-STAT5 in precancerous lesions.

BACKGROUND: Psychiatric medications are widely prescribed in the USA. Many antipsychotics cause serum hyperprolactinemia as an adverse side effect; prolactin-Janus kinase 2 (JAK2)-signal transducer and activator of transcription 5 (STAT5) signaling both induces cell differentiation and suppresses apoptosis. It is controversial whether these antipsychotics increase breast cancer risk. METHODS: We investigated the impact of several antipsychotics on mammary tumorigenesis initiated by retrovirus-mediated delivery of either ErbB2 or HRas or by transgenic expression of Wnt-1. RESULTS: We found that the two hyperprolactinemia-inducing antipsychotics, risperidone and pimozide, prompted precancerous lesions to progress to cancer while aripiprazole, which did not cause hyperprolactinemia, did not. We observed that risperidone and pimozide (but not aripiprazole) caused precancerous cells to activate STAT5 and suppress apoptosis while exerting no impact on proliferation. Importantly, we demonstrated that these effects of antipsychotics on early lesions required the STAT5 gene function. Furthermore, we showed that only two-week treatment of mice with ruxolitinib, a JAK1/2 inhibitor, blocked STAT5 activation, restored apoptosis, and prevented early lesion progression. CONCLUSIONS: Hyperprolactinemia-inducing antipsychotics instigate precancerous cells to progress to cancer via JAK/STAT5 to suppress the apoptosis anticancer barrier, and these cancer-promoting effects can be prevented by prophylactic anti-JAK/STAT5 treatment. This preclinical work exposes a potential breast cancer risk from hyperprolactinemia-inducing antipsychotics in certain patients and suggests a chemoprevention regime that is relatively easy to implement compared to the standard 5-year anti-estrogenic treatment in women who have or likely have already developed precancerous lesions while also requiring hyperprolactinemia-inducing antipsychotics.

Mucuna pruriens (L.) DC chemo sensitize human breast cancer cells via downregulation of prolactin-mediated JAK2/STAT5A signaling.

ETHNOPHARMACOLOGICAL RELEVANCE: Mucuna pruriens (L.) DC (MP) is an ancient Indian medicinal plant traditionally used to treat Parkinson's disease. L-Dopa (LD), precursor of dopamine is abundantly found in the seeds of MP. L-dopa is a natural inhibitor of prolactin (PRL) hormone which is required to maintain lactation in women but it's over production (hyperprolactinemia) plays critical role in advancement of breast cancer. AIM OF THE STUDY: We aim to examine the pharmacological effect of LD and MP on this hyperprolactinemia associated breast cancer and related signaling for effective management of the disease. We also investigated chemo-sensitizing effect of MP on hyperprolactinemia-mediated cisplatin resistance. MATERIALS AND METHODS: Methanolic seed extract of MP were prepared and analysed using HPLC. Effect of LD and MP on the cellular viability of breast cancer cells (T47D, MCF-7, MDA-MB-468 and MDA-MB-231) were evaluated using MTT assay. Further, effect of LD and MP on colony forming potential, DNA damage, cell cycle distribution and apoptosis was determined using agar/agarose method, comet assay and annexin and PI method followed by FACS analysis. To reveal the molecular mechanism involved in the anti-cancer activity of MP, transcriptional and translational level analysis of the key proteins involved in the PRL-mediated signaling, was performed using RT-PCR and western blot analysis. The effect of MP extract on PRL-mediated signaling was validated using dopaminergic agonist bromocriptine. MP extract and cisplatin was given in different combination with appropriate controls to check their effect on chemo-resistivity of breast cancer cells. RESULTS: Our results demonstrated that MP seed extract has the potential to inhibit cellular proliferation of PRL expressing T47D and MCF-7 breast cancer cells via induction of DNA damage, G1 phase of cell cycle arrest and apoptosis more effectively as compare to LD. Further, MP-mediated anti-cancerous effect was associated with the downregulation of PRL expression, further suppressing the JAK2/STAT5A/Cyclin D1 signaling pathway which has been validated using dopaminergic agonist bromocriptine. Cancer-related hyperprolactinemia confers cisplatin resistance, we observed that MP via PRL inhibition, enhances cisplatin efficacy after their combinatorial treatment in breast cancer cells. CONCLUSIONS: Collectively, our study suggests that MP could be recommended as dietary supplement along with the chemotherapeutic agents against breast cancer.

Administration of Cabergoline Contributes to Preserving Fertility in Young Hyperprolactinemic Patients With Endometrial Cancer Treated With Medroxyprogesterone Acetate.

BACKGROUND: An association between high levels of serum prolactin and endometrial cancer (EC) has been reported. However, the effect of antiprolactin drugs on hyperprolactinemic patients with EC has not been determined. The aim of this study was to confirm the effect of cabergoline on young hyperprolactinemic patients treated with medroxyprogesterone acetate (MPA) for the preservation of fertility. METHODS: A retrospective observational study was conducted to identify patients with atypical endometrial hyperplasia or early-stage EC aged 40 years or younger who were treated with oral MPA in Kumamoto University Hospital between 1998 and 2016. RESULTS: Thirty-four patients were identified and divided into two groups of 17 patients each, including a nonadministration of cabergoline group (noncabergoline group) and an administration of cabergoline group (cabergoline group). The ratio of pathological diagnoses of EC in the noncabergoline group was significantly lower than that in the cabergoline group (29.4% vs 70.6%, P = 0.016). The mean serum prolactin levels showed a significant decrease after the administration of cabergoline in the cabergoline group (25.2 [24.0] vs 5.2 [4.2] ng/mL, P = 0.003), and this decreased level was also significantly lower than that in the noncabergoline group (5.2 [4.2] vs 12.0 [5.0] ng/mL, P < 0.001). Kaplan-Meier analysis conducted for 150 months revealed that the estimated mean period until hysterectomy in the noncabergoline group was significantly shorter than that in the cabergoline group (83.5 vs 140.8 months, P = 0.007). Significant differences were observed in EC but not atypical endometrial hyperplasia based on histological classification (25.6 vs 138.0 months, P = 0.001). CONCLUSIONS: The administration of cabergoline may contribute to preserving fertility in young hyperprolactinemic patients with EC who were treated with MPA.

Rejuvenating Effect of Long-Term Insulin-Like Growth Factor-I Gene Therapy in the Hypothalamus of Aged Rats with Dopaminergic Dysfunction.

The aging female rat constitutes an interesting model of spontaneous and progressive age-related dopaminergic dysfunction as it allows assessing new therapeutic strategies for Parkinson's disease. Insulin-like growth factor I (IGF-I) is emerging as a powerful neuroprotective molecule, strongly induced in the central nervous system after different insults. We constructed a helper-dependent recombinant adenoviral vector (HDRAd-IGFI) harboring the gene for rat IGF-I. This was used to implement long-term IGF-I gene therapy in the hypothalamus of aged female rats, which display hypothalamic dopaminergic (DA) dysfunction and, as a consequence, chronic hyperprolactinemia. Rejuvenating long-term IGF-I gene therapy was implemented in young (3 months) and aged (24 months) female rats, which received a single intrahypothalamic injection of 4 × 109 viral particles of either HD-RAd-IGFI or HD-RAd-DsRed (control vector) and were sacrificed 119 days postinjection. In the young animals, neither vector modified serum prolactin (PRL) levels, but in the RAd-IGFI-injected aged rats a nearly full reversion of their hyperprolactinemic status was recorded. Morphometric analysis revealed a significant increase in the total number of tyrosine hydroxylase (TH)-positive cells in the hypothalamus of experimental compared with control aged animals (5874 ± 486 and 3390 ± 498, respectively). Our results indicate that IGF-I gene therapy in aged female rats is highly effective in rejuvenating the hypothalamic DA neuron groups.

Cooperative Synthesis of Dopamine in Rat Mediobasal Hypothalamus as a Compensatory Mechanism in Hyperprolactinemia.

Dopamine (DA), synthesized in the mediobasal hypothalamus by dopaminergic neurons containing two enzymes of DA synthesis - tyrosine hydroxylase and decarboxylase of aromatic L-amino acids, or by monoenzymatic non-dopaminergic neurons containing one DA synthesis enzyme in cooperation, is known to have an inhibitory effect on prolactin secretion. Deterioration of this inhibitory control leads to an increase in prolactin concentration in the blood and to the development of hyperprolactinemia syndrome. In a rat model of hyperprolactinemia induced by administration of a neurotoxin causing degeneration of dopaminergic and noradrenergic neurons, the level of DA first decreases, leading to an increase in prolactin level (decompensation stage), while later both levels are restored to normal (compensation stage). However, the mechanism of such compensation is still not clear. The aim of the present study was to analyze whether the increase in cooperative synthesis of DA by monoenzymatic neurons during hyperprolactinemia is a manifestation of a compensatory mechanism representing a particular case of neuroplasticity. The level of cooperative synthesis in the hyperprolactinemia model and in the control was estimated as the level of synthesis of DA and L-dihydroxyphenylalanine (L-DOPA) - an intermediate product of DA synthesis, when L-DOPA transfer from neurons containing tyrosine hydroxylase into neurons containing aromatic L-amino acid decarboxylase is inhibited. The level of DA synthesis during the decompensation stage was not changed, while during the compensation stage it was lower than the control. Along with a reduction in DA level, during the compensation stage an increase in the extracellular L-DOPA level in the medium was detected. Thus, the compensation of DA deficiency after degeneration of dopaminergic neurons in the mediobasal hypothalamus is due to the increase in cooperative synthesis of DA by monoenzymatic neurons containing one of the complementary enzymes of the DA synthesis pathway.