Effect of prolactin and dopaminergic drugs on uterine response to chronic estrogen exposure

Lomens-P0 (mixed extracts of Hordeum vulgare and Chrysanthemum zawadskii) regulate the expression of factors affecting premenstrual syndrome symptoms

BACKGROUND/OBJECTIVES

Premenstrual syndrome (PMS) is a disorder characterized by repeated emotional, behavioral, and physical symptoms before menstruation, and the exact cause and mechanism are uncertain. Hyperprolactinemia interferes with the normal production of estrogen and progesterone, leading to PMS symptoms. Thus, we judged that the inhibition of prolactin hypersecretion could mitigate PMS symptoms.

MATERIALS/METHODS

Hordeum vulgare L. extract (HVE), Chrysanthemum zawadskii var. latilobum extract (CZE), and Lomens-P0 the mixture of these extracts were tested in subsequent experiments. The effect of extracts on prolactin secretion at the in vitro level was measured in GH3 cells. Nitric oxide and pro-inflammatory mediator expression were measured in RAW 264.7 cells to confirm the anti-inflammatory effect. Also, the hyperprolactinemic Institute for Cancer Research (ICR) mice model was used to measure extract effects on prolactin and hormone secretion and uterine inflammation.

RESULTS

Anti-inflammatory effects of and prolactin secretion suppress by HVE and CZE were confirmed through in vitro experiments (P < 0.05). Treatment with Lomens-P0 inhibited prolactin secretion (P < 0.05) and restored normal sex hormone secretion in the hyperprolactinemia mice model. In addition, extracts significantly inhibited the expression of pro-inflammatory biomarkers, including interleukin-1β, and -6, tumor necrosis factor-α, inducible nitric oxide synthase, and cyclooxygenase-2 (P < 0.01). We used high-performance liquid chromatography analyses to identify tricin and chlorogenic acid as the respective components of HVE and CZE that inhibit prolactin secretion. The Lomens-P0, which includes tricin and chlorogenic acid, is expected to be effective in improving PMS symptoms in the human body.

CONCLUSIONS

The Lomens-P0 suppressed the prolactin secretion in hyperprolactinemia mice, normalized the sex hormone imbalance, and significantly suppressed the expression of inflammatory markers in uterine tissue. This study suggests that Lomens-P0 may have the potential to prevent or remedy materials to PMS symptoms.

Prolactin concentration in various stages of endometriosis in infertile women

OBJECTIVE

The relation between excessive prolactin and endometriosis-related infertility is debatable. Anovulation or defective luteal phase occurs frequently due to hyperprolactinemia in subfertile women. In this investigation, we evaluated the association between serum prolactin levels and the severity of endometriosis.

METHODS

This retrospective cohort study carried out at the Babol Infertility Research Center looked into the baseline serum prolactin levels of 114 infertile women with endometriosis and compared them to the levels seen in 101 infertile women without endometriosis (controls). Statistical analysis included independent t-test, chi-square, Welch test and ROC curve analysis.

RESULTS

Infertile women with endometriosis had significantly higher serum prolactin levels than infertile women without endometriosis (p=0.003). A significant difference was detected between controls and individuals with endometriosis stages III/IV (p-value=0.009). Prolactin was found to have diagnostic value to detect endometriosis stages III/IV vs. stages I/II in AUC=0.65, 95% CI (0.55, 0.76). Prolactin values with a cut off set at 20.08 ng/mL had a sensitivity of 0.74 and specificity of 0.54 in detecting disease stages III/IV vs. I/II. The prognostic capability of prolactin in detecting endometriosis in cases vs. controls by ROC curve analysis had an AUC=+0.67, 95% CI (0.60, 0.74). Prolactin values with a cut off set at 17.5 ng/mL had a sensitivity of 0.64 and specificity of 0.63 in segregating subjects with and without endometriosis.

CONCLUSION

Higher prolactin levels were observed in infertile women with more severe endometriosis when compared to infertile women without endometriosis. Prolactin levels act as a probable prognostic biomarker to detect endometriosis stages III/IV vs. I/II and segregate infertile women with endometriosis from subjects without endometriosis.

Sex Hormones Response to Physical Hyperoxic and Hyperbaric Stress in Male Scuba Divers: A Pilot Study

The use of hyperbaric oxygen plays a significant role in many aspects of medicine. However, there are few studies that analyzed the role of hyperbaric oxygen, in addition to physical exercise, on the endocrine profile. The aim of this study was to compare changes in plasma male sex hormones after hyperbaric physical exercise with different hyperbaric oxygen pre-conditionings. We recruited six healthy, well-trained recreational male divers. Concentrations of prolactin (PRL), follicle-stimulating hormone (FSH), luteotrophic hormone (LH), cortisol, 17-β estradiol (E2), and total testosterone (TT) were measured in venous blood immediately after four different study conditions. Exercise increased PRL and hyperbaric oxygen potentiated this effect. Hyperbaria stimulated the E2 reduction and hyperoxia partially inhibited this reduction. Hyperbaria, but not hyperoxia, stimulated the TT reduction. There were no changes in FSH, LH, and cortisol. The increase in PRL likely reflects a stress response after physical exercise, amplified by hyperbaric oxygen. TT reduction may be interpreted as an acute and transient fertility impairment. Age, blood pressure, and BMI were taken into account as covariates for statistical analyses, and they significantly affected the results, in particular TT. These data open new insight into the role of E2 and PRL in male endocrine adaptive responses.

Effects of sulpiride and ethylene glycol monomethyl ether on endometrial carcinogenicity in Donryu rats

Sulpiride and ethylene glycol monomethyl ether (EGME) are known ovarian toxicants that stimulate prolactin (PRL) secretion, resulting in hypertrophy of the corpora lutea and increased progesterone (P4) production. The purpose of the present study was to investigate how the PRL stimulatory agents affected uterine carcinogenesis and to clarify the effects of PRL on endometrial adenocarcinoma progression in rats. Ten-week-old female Donryu rats were treated once with N-ethyl-N'-nitro-N-nitrosoguanidine (20 mg kg(-1) ), followed by treatment with sulpiride (200 ppm) or EGME (1250 ppm) from 11 weeks of age to 12 months of age. Sulpiride treatment inhibited the incidence of uterine adenocarcinoma and precancerous lesions of atypical endometrial hyperplasia, whereas EGME had no effect on uterine carcinogenesis. Sulpiride markedly prevented the onset of persistent estrus throughout the study period, and EGME delayed and inhibited the onset of persistent estrus. Moreover, sulpiride-treated animals showed high PRL and P4 serum levels without changes in the levels of estradiol-17β, low uterine weights and histological luteal cell hypertrophy. EGME did not affect serum PRL and P4 levels. These results suggest that the prolonged low estradiol-17β to P4 ratio accompanied by persistent estrous cycle abnormalities secondary to the luteal stimulatory effects of PRL may explain the inhibitory effects of sulpiride on uterine carcinogenesis in rats. Copyright © 2015 John Wiley & Sons, Ltd.

Prolactin directly enhances bone turnover by raising osteoblast-expressed receptor activator of nuclear factor kappaB ligand/osteoprotegerin ratio

Hyperprolactinemia leads to high bone turnover as a result of enhanced bone formation and resorption. Although its osteopenic effect has long been explained as hyperprolactinemia-induced hypogonadism, identified prolactin (PRL) receptors in osteoblasts suggested a possible direct action of PRL on bone. In the present study, we found that hyperprolactinemia induced by anterior pituitary transplantation (AP), with or without ovariectomy (Ovx), had no detectable effect on bone mineral density and content measured by dual-energy X-ray absorptiometry (DXA). However, histomorphometric studies revealed increases in the osteoblast and osteoclast surfaces in the AP rats, but a decrease in the osteoblast surface in the AP+Ovx rats. The resorptive activity was predominant since bone volume and trabecular number were decreased, and the trabecular separation was increased in both groups. Estrogen supplement (E2) fully reversed the effect of estrogen depletion in the Ovx but not in the AP+Ovx rats. In contrast to the typical Ovx rats, bone formation and resorption became uncoupled in the AP+Ovx rats. Therefore, hyperprolactinemia was likely to have some estrogen-independent and/or direct actions on bone turnover. Osteoblast-expressed PRL receptor transcripts and proteins shown in the present study confirmed our hypothesis. Furthermore, we demonstrated that the osteoblast-like cells, MG-63, directly exposed to PRL exhibited lower expression of alkaline phosphatase and osteocalcin mRNA, and a decrease in alkaline phosphatase activity. The ratios of receptor activator of nuclear factor kappaB ligand (RANKL) and osteoprotegerin (OPG) proteins were increased, indicating an increase in the osteoclastic bone resorption. The present data thus demonstrated that hyperprolactinemia could act directly on bone to stimulate bone turnover, with more influence on bone resorption than formation. PRL enhanced bone resorption in part by increasing RANKL and decreasing OPG expressions by osteoblasts.

Uterine response to estradiol under action of chorionic gonadotropin in mice

This work examined the effect of chorionic gonadotropin on proliferative and morphogenetic reactions in the uterus under short- and long-term estrogen treatments. Ovariectomized mice received a single injection with estradiol dipropionate (2 micro g per 100 g; subcutaneously, sc) or vehicle and injections with human chorionic gonadotropin (10 IU per 100 g; sc) or vehicle twice a day for 2 days. Other groups of animals received injections with estradiol once a week or vehicle and injections with chorionic gonadotropin or vehicle once a day for 30 days. The uteri were removed 48 h after the last estradiol or vehicle injection. In animals treated with estradiol and chorionic gonadotropin for a month, the incidence of atypical endometrial hyperplasia was significantly higher. In animals treated with estradiol and chorionic gonadotropin for 2 days or for a month, uterine mass was slightly increased, the number of mitotic cells and BrdU-labeled cells was greater in luminal epithelium, glandular epithelium, stromal and myometrial cells, whereas the expression of estrogen receptors-alpha was lower in all uterine compartments, than in control. In mice who received estradiol and chorionic gonadotropin for 2 days, levels of beta-catenin and glycogen synthase kinase-3beta in luminal and glandular epithelia were lower. In animals treated with estradiol and chorionic gonadotropin for a month, the level of beta-catenin was slightly higher, and the expression of glycogen synthase kinase-3beta was lower in luminal and glandular epithelia. Thus, chorionic gonadotropin exerts estradiol-induced proliferative and morphogenetic changes in the uterus. This action of chorionic gonadotropin is associated with decreased expression of estrogen receptors-alpha and with changes in expression of beta-catenin and glycogen synthase kinase-3beta in the uterus.

Expression of estrogen receptor-alpha, glucocorticoid receptor, beta-catenin and glycogen synthase kinase-3beta in the uterus of mice following long-term treatment with estrogen and glucocorticoid hormones

BACKGROUND

It has been shown that long-term glucocporticoid administration to chronically estradiol-treated mice decreases uterine weight, proliferation in all uterine tissues, the number of perpendicularly oriented mitoses in uterine epithelia and the incidence of atypical endometrial hyperplasia. However, mechanisms of chronic glucocorticoid action on estrogen-dependent processes in the uterus are unclear.

METHODS AND RESULTS

Results of present research showed that adding of glucocorticoid dexamethasone (in drinking water, 2mg/l) to estradiol-treated mice led to a decrease in the level of glucocorticoid receptor, to an increase in levels of estrogen receptor-alpha, beta-catenin and glycogen synthase kinase-3beta in uterine tissues of ovariectomized mice at 30, 60 and 90 days of the treatment. When vehicle was used instead estradiol, dexamethasone did not produce detectable changes in all parameters tested at all periods of observation.

CONCLUSION

Results allow to conclude that estrogen and glucocorticoid receptors, beta-catenin and glycogen synthase kinase-3beta are involved in estrogen-dependent changes in uterine morphology and hyperplasia formation.