Decreased Serum Prolactin Levels Research Articles

Wheel Running During Pregnancy Alleviates Anxiety-and Depression-Like Behaviors During the Postpartum Period in Mice: The Roles of NLRP3 Neuroinflammasome Activation, Prolactin, and the Prolactin Receptor in the Hippocampus.

Despite the increase in the prevalence of postpartum depression among maternal disorder, its treatment outcomes remain suboptimal. Studies have shown that exercise can reduce postpartum depressive episodes in the mother, but the effects of exercise during pregnancy on maternal behavior and the potential mechanisms involved remain poorly understood. From the second day of pregnancy to the day of birth, dams exercised for 1h a day by running on a controlled wheel. The maternal behaviors of the dams were assessed on postpartum day 2 to postpartum day 8. Chronic restraint stress was applied from postpartum day 2 to day 12. Blood was collected on postpartum days 3 and 8, then subjected to ELISA to determine the serum concentration of prolactin. The weight of each dam and the food intake were recorded. Anxiety- and depression-like behavioral tests were conducted, and hippocampal neuroinflammation and prolactin receptor levels were measured. The dams exhibited elevated levels of anxiety and depression, decreased serum prolactin levels, decreased prolactin receptor expression, and activation of NLRP3-mediated neuroinflammation in the hippocampus following the induction of postpartum chronic restraint stress, which were reversed with controlled wheel running during pregnancy. Overall, the findings of this study revealed that the preventive effects of exercise during pregnancy on postpartum anxiety-and depression-like behaviors were accompanied by increased serum prolactin levels, hippocampal prolactin receptor expression and hippocampal NLRP3-mediated neuroinflammation.

Evaluation of Serum Estrogen, Progesterone, Prolactin and Testosterone in Patients of Melasma

Objective: To evaluate the estrogen, progesterone, Prolactin and testosterone serum levels in melasma patients.
 Study Design: Comparative cross-sectional study.
 Place and Duration of Study: Dermatology Department, Fauji Foundation Hospital, Rawalpindi Pakistan, from Jul to Dec2020.
 Methodology: A total of 40 patients with melasma and 40 without melasma were included in this study. The study comprisedfemale melasma patients aged 20 to 50 years old. All participants were tested for serum estrogen, progesterone, Prolactin andtestosterone levels using immunoassay in the follicular phase (9th day) of the menstrual cycle.
 Results: The statistically significant increase in serum progesterone (p=0.001) was found in patients with melasma. Asignificant decrease in prolactin levels (p=0.0001) was found in patients with melasma. No association was found betweenGroup-1 and Group-2 regarding serum estradiol and testosterone (p=0.070 and p=0.461 respectively)
 Conclusion: Patients with melasma have increased progesterone levels and decreased serum prolactin levels.

The impact of oral hormonal contraception on metformin action on hypothalamic-pituitary-thyroid axis activity in women with diabetes and prediabetes: A pilot study.

The impact of metformin on thyrotropin levels is sex-dependent. No previous study has assessed whether sex steroids determine metformin action on thyrotrope and thyroid cell functioning. The aim of the present study was to compare the effect of this agent on hypothalamic-pituitary-thyroid axis activity and thyroid function tests between women receiving oral contraceptive pills and women not using any contraception. The study population included 52 women with subclinical hypothyroidism and prediabetes or diabetes, 20 of whom had been using oral contraceptive pills for at least 12months before the beginning of the study. Over the entire study period (4months), all participants received oral metformin (1.7-3g daily). Circulating levels of glucose, insulin, thyrotropin, free thyroid hormones, oestradiol, gonadotropins and prolactin were measured, while the structure parameters of thyroid homeostasis and the degree of insulin sensitivity were calculated at the beginning and at the end of the study. The study groups differed in oestradiol, gonadotropins and prolactin levels and in structure parameter inference approach (SPINA)-GT. In both groups, metformin reduced glucose levels, homeostasis model assessment 1 of insulin resistance index (HOMA1-IR), thyrotropin levels and Jostel's thyrotropin index, as well as increased SPINA-GT. In women receiving oral contraceptive pills, the drug slightly decreased serum prolactin levels. The impact on metformin on HOMA1-IR, thyrotropin, prolactin, Jostel's thyrotropin index and SPINA-GT was more pronounced if women received oral contraception, as well as more pronounced in patients treated with higher doses of this agent. Treatment-induced changes in thyrotropin and Jostel's thyrotropin index correlated with their baseline values, baseline levels of oestradiol and gonadotropins, as well as with the degree of a reduction in HOMA1-IR. This study is the first one to have shown that oral oestrogens potentiate the effect of metformin on hypothalamic-pituitary-thyroid axis activity.

Effects of prolactin on the results of echocardiography and daily multichanel intraluminal impedans-pH-monitoring of the esophagus of patients with stable angina of effort and gastroesophageal reflux disease in the dynamics of treatment

Objective — to establish the effect of complex therapy with the addition of meldonium on the results of echocardio­graphy, daily multichanel intraluminal impedans-pH-monitoring (DMII-pH-M) of the esophagus and serum prolactin level in patients with stable angina of tension (SAT) and gastroesophageal reflux disease (GERD) in the conditions of comorbidity.Materials and methods. The study included 88 patients with SAT I—II FC with comorbid endoscopically positive GERD, which was divided into 2 groups: in group 1 (43 persons) received treatment: antiaggregant (clopidogrel), β-blocker (bisoprolol), statin (rosuvastatin), prolonged Nitric Oxide Donors donor and nitroglycerin in angina pectoris, proton pump inhibitor (rabeprazole), prokinetic (domperidone) and antacid as needed. Patients in group 2 (45 subjects) received basic therapy with SAT and GERD, with the exception of prokinetics and NO donors, only nitroglycerin, if necessary, and additionally meldonium capsules 500 mg 2 g/d for 30 days. Echocardiography, DMII-pH-M of the esophagus were performed in all patients enrolled in the study and serum levels of prolactin were determined before and at day 30 of treatment.Results and discussion. Blood serum of patients with SAT with comorbid GERD remains high when prokinetic is received and adversely affects the overall contractility of the myocardium of the left ventricle, esophagitis regression, confirmation is correlated0 (r = –0.73) between the serum PL level and emission fraction of left ventricle; MNBI (mean nocturnal baseline impedance) (r = –0.71) in group 1 and (r = –0.7) in group 2. Against the background of correction of baseline therapy for SAT and GERD with cancellation of prokinetic intake and, with additional prescription of meldonium, we observed a statistically significant (р < 0.05) decrease in prolactin level (OR = 3.9609, 95 % CI 1.1761—13.3398, p < 0.0263), decrease in total number of refluxes per day (OR = 14.1, 95 % CI 4.9739—40.2144, p < 0.0001) (р < 0.05), increase of PSPW (postreflux swallow induced peristaltic wave) (OR = 3.9, 95 % CI 1.5845—9.4767, p < 0.003) (р < 0.05), MNBI (р < 0.05) and emission fraction of left ventricle (OR = 4.2, 95 % CI 1.4802—12.2029, p = 0.0072) (p < 0.05), compared with group 1.Conclusions. The correction of the basic therapy of the SAT and GERD with the prokinetics’ cancellation and the additional use of meldonium resulted in the decrease of serum prolactin levels, which closely correlated with the main indicators of echocardiography and DMII-pH-M, manifesting in an increase in the general contractility of the left myocardium ventricle and lower esophageal sphincter, increasing of the kinetic function of the esophagus and improving the regenerative capabilities of its mucous membrane.

A Case Series of Temozolomide in the Management of Refractory Prolactinomas

Objective: To report three cases of refractory prolactinomas treated with Temozolomide (TMZ). Background: Prolactinomas account for 40% of pituitary adenomas. Dopamine agonists (DA) are the first line of treatment followed by surgical resection and radiation. TMZ is an oral chemotherapeutic agent used in gliomas, which has been given to patients with prolactinomas refractory to conventional treatments. Methods: Retrospective chart review was conducted for refractory prolactinoma patients treated between 2008 and 2017 at UT Southwestern Medical Center (UTSW). Three patients with refractory prolactinomas received oral TMZ at UTSW. Results: All three patients demonstrated improvement in symptoms upon TMZ treatment, markedly decreased serum prolactin levels (SPRL), as well as radiographic decrease in tumor size. Conclusion: TMZ is well tolerated and is a potentially effective treatment for refractory prolactinomas.

SERUM PROLACTIN LEVELS IN TYPE-II DIABETES MELLITUS WITH RETINOPATHY PATIENTS IN AND AROUND HYDERABAD

Background & Objectives: Diabetes is a disease of metabolic dysregulation. Hyperglycemia and oxidative stress play a role in the development of late diabetic complications. Increased retinal vasopermeability occurs early in diabetes and is crucial for the development of sight-threatening diabetic retinopathy. Serum prolactin is proteolytically processed to vasoinhibins that inhibit the excessive retinal vasopermeability related to diabetic retinopathy. The aim is to study the role of serum prolactin and lipid profile in the pathogenesis of retinopathy in type 2 diabetics and to correlate the changes in serum prolactin levels. Methods: A case control study was done with 90 patients divided into 3 groups (healthy controls, Type 2 Diabetes without retinopathy and Type 2 Diabetes with retinopathy) with inclusion and exclusion criteria. Fasting blood samples were collected and fasting plasma glucose, serum Prolactin were measured. Multiple comparisons between different groups were done using ANOVA test. Results: In the present study decreased serum prolactin levels were observed in patients of Type 2 Diabetes with retinopathy compared to Type 2 Diabetes without retinopathy and controls. Mean ± S.D of Fasting plasma glucose, was highest in Group 3. Mean ± S.D of serum prolactin (7.737 ± 2.63) was low in Group 3. Interpretations & Conclusion: The circulating levels of prolactin were decreased in patients with diabetic retinopathy due to glycosylation and were higher in diabetic patients without retinopathy and healthy controls. Increased prolactin levels influence the progression of retinopathy after its intraocular conversion to vasoinhibins which can reduce the pathological retinal vasopermeability in diabetes and increase in prolactin can be considered to have protective role in pathogenesis of diabetic retinopathy and also may be considered as a treatment option for retinopathy. Key words: Prolactin; Diabetic retinopathy; Vasoinhibins; Retinal vasopermeability.

Adjunctive metformin for antipsychotic-induced hyperprolactinemia: A systematic review

This systematic review examines adjunctive metformin therapy for the treatment of antipsychotic-induced hyperprolactinemia. A computerized search of databases in Chinese and the international databases in English provided three trials with a total of 325 patients including one randomized clinical trial (RCT) and two observational studies (single-group, before-after design). A meta-analysis could not be conducted. The quality of evidence ranged from “very low” to “moderate”. Metformin patients had a significant decrease in serum prolactin level with a mean of 54.6μg/l in the three trials. In the RCT, menstruation restarted in 67% of those with menstrual disturbances versus 5% in placebo. In one observational study, 91% of patients no longer had signs or symptoms of galactorrhea. In the RCT, adverse drug reactions (ADRs) occurred at similar incidence rates among metformin and placebo patients, except that no significant increases in nausea, insomnia and agitation occurred which were not associated with discontinuations. Our systematic review indicated that adjunctive metformin significantly lowered prolactin level and relieved prolactin-related symptoms in patients with antipsychotic-induced hyperprolactinemia. Future higher quality RCTs need to verify the currently available limited evidence based on three trials which suggest that adjunctive metformin may be used effectively and safely for antipsychotic-induced hyperprolactinemia.

A Case of Hyperprolactinemia Induced by Paliperidone Palmitate: the Role of Carbegoline.

We describe a case of a man of 39 years, treated with paliperidone palmitate after treatment failure with other antipsychotics, including those of (conventional and atypical) oral and injectable, and developed secudary hyperprolactinemia. Evaluate the effectiveness of the method for management of hyperprolactinemia secondary to the use of second generation long-acting antipsychotic. Follow-up during 18 months in outpatient mental health. In the period the patient remained stable with the use of paliperidone palmitate. Serum prolactin levels were obtained at baseline, and every two months. The patient had sexual dysfunction as the main complaint. Initially adopted the gradual reduction in dosage of antipsychotic 150 mg / month to 75 mg / month, however, the patient had psychotic relapse. So, we decided to keep the dose of paliperidone palmitate and associate the drug cabergoline at a dose of 0.5 mg per week, and serum prolactin levels were normalized. There was a decrease in serum prolactin levels as well as the related sexual sphere, with the addition of cabergoline to treatment with paliperidone palmitate symptoms. The long-acting antipsychotic paliperidone palmitate is a safe and effective medicine to control the symptoms of schizophrenia. Hyperprolactinemia is a rare side effect associated with this psychotropic drug, which can be handled without difficulty with antidotes. The cabergoline proved to be an effective and free from adverse side efects alternative to reduce the levels of hyperprolactinemia secondary to use of paliperidone palmitate effects, including sexual dysfunction relieving.

Local transformations of androgens into estradiol by aromatase P450 is involved in the regulation of prolactin and the proliferation of pituitary prolactin-positive cells.

In previous studies we demonstrated the immunohistochemical expression of aromatase in pituitary cells. In order to determine whether pituitary aromatase is involved in the paracrine regulation of prolactin-producing pituitary cells and the physiological relevance of pituitary aromatase in the control of these cells, an in vivo and in vitro immunocytochemical and morphometric study of prolactin-positive pituitary cells was carried out on the pituitary glands of adult male rats treated with the aromatase antagonist fadrozole. Moreover, we analyzed the expression of mRNA for the enzyme in pituitary cells of male adult rats by in situ hybridization. The aromatase-mRNA was seen to be located in the cytoplasm of 41% of pituitary cells and was well correlated with the immunocytochemical staining. After in vivo treatment with fadrozole, the size (cellular and nuclear areas) of prolactin cells, as well as the percentage of prolactin-positive cells and the percentage of proliferating-prolactin cells, was significantly decreased. Moreover, fadrozole decreased serum prolactin levels. In vitro, treatment with fadrozole plus testosterone induced similar effects on prolactin-positive cells, inhibiting their cellular proliferation. Our results suggest that under physiological conditions aromatase P450 exerts a relevant control over male pituitary prolactin-cells, probably transforming testosterone to estradiol in the pituitary gland.

Effect of the Addition of Aripiprazole on Hyperprolactinemia Associated With Risperidone Long-Acting Injection

We sought to assess the effect of the addition of a fixed dose of 5 mg daily of aripiprazole on hyperprolactinemia induced by risperidone long-acting injectable (RLAI) treatment in patients with chronic psychoses and the adverse events related to the addition of aripiprazole and its impact on the disease. This is an open uncontrolled clinical trial with 13 patients with a severe mental disorder (schizophrenia and other unspecified psychoses) treated with RLAI and with increased serum prolactin levels. Subjects received the addition of a fixed dose of 5 mg daily of aripiprazole for 3 months. The main efficacy outcome was the change in serum prolactin levels after 3 months of treatment. Twelve of the 13 patients showed a decrease in serum prolactin levels (81 ± 46 μg/L at baseline vs 42 ± 21 μg/L at month 1, P < 0.001, 52% mean reduction). In 2 patients, prolactin levels reverted normality. In 8 patients who continued treatment for 2 more months, the decrease in prolactin levels was maintained. Symptoms associated with hyperprolactinemia improved, and no worsening of the Clinical Global Impression Scale scores was observed. The adverse effects due to the addition of aripiprazole were mild and transient. The addition of aripiprazole 5 mg daily to RLAI was associated with a significant decrease in hyperprolactinemia levels and no major additional toxicity in patients with chronic psychosis.

Changes in prolactin levels and sexual function in young psychotic patients after switching from long-acting injectable risperidone to paliperidone palmitate

Hyperprolactinaemia is a significant side effect of antipsychotic medications and may cause sexual dysfunction. The aim of our study was to assess the effect of switching from long-acting injectable (LAI) risperidone to paliperidone palmitate (PP) on sexual function and prolactin levels in patients with psychosis. We carried out a prospective observational study during a 3-month period that involved 11 patients with psychosis treated with risperidone-LAI who suffered from hyperprolactinaemia and who were then switched to PP. Two assessments were completed: the first one before the switch and the second one 3 months after the switch. These assessments measured sexual function using the Arizona Sexual Experience Scale and assessed prolactin levels. Our results showed a significant decrease in serum prolactin levels (P=0.041). We observed a four-fold reduction in clinically significant sexual dysfunction that is suggestive of benefit, although the sample size is too small to be sure. Our study suggests that prolactin levels seem to decrease after switching from risperidone-LAI to PP in patients with a psychotic disorder.

P-692 - Hyperprolactinaemia and psychosis

Hyperprolactinaemia causes hypogonadotropic hypogonadism. Hyperprolactinaemia could be pre-existing in some patients with schizophrenia. Dopamine is the most important prolactin inhibiting factor, while dopaminergic hyperactivity has been implicated to the pathophysiology of psychosis. We present the case of a patient with hypogonadism secondary to chronic, untreated hyperprolactinaemia who developed acute psychotic symptoms. Psychotic symptoms resolved soon after treatment with aripiprazole in conjunction with cabergoline, with a concomitant decrease in serum prolactin levels. An interesting cause effect relationship of hyperprolactinaemia and psychosis has been suggested

Prolactin-mediated regulation of lipid biosynthesis genes in vivo in the lactating mammary epithelial cell

Prolactin (PRL) is known to play an essential role in mammary alveolar proliferation in the pregnant mouse, but its role in lactation has been more difficult to define. Genetic manipulations that alter expression of the PRL receptor and its downstream signaling molecules resulted in developmental defects that may directly or indirectly impact secretory activation and lactation. To examine the in vivo role of PRL specifically in lactation, bromocriptine (BrCr) was administered every 8 h to lactating mice on the second day postpartum, resulting in an ~95% decrease in serum PRL levels. Although morphological changes in secretory alveoli were slight, by 8 h of BrCr, pup growth was inhibited significantly. Phosphorylated STAT5 fell to undetectable levels within 4 h. Decreased milk protein gene expression, β-casein, and α-lactalbumin, was observed after 8 h of treatment. To assess mammary-specific effects on lipid synthesis genes, we isolated mammary epithelial cells (MECs) depleted of mammary adipocytes. Expression of genes involved in glucose uptake, glycolysis, pentose phosphate shunt, de novo synthesis of fatty acids, and biosynthesis of triacylglycerides was decreased up to 19-fold in MECs by just 8 h of BrCr treatment. Glands from BrCr-treated mice showed a twofold reduction in intracellular cytoplasmic lipid droplets and a reduction in cytosolic β-casein. These data demonstrate that PRL signaling regulates MEC-specific lipogenic gene expression and that PRL signals coordinate the milk synthesis and mammary epithelial cell survival during lactation in the mouse.

Infertility and obstructive sleep apnea: the effect of continuous positive airway pressure therapy on serum prolactin levels

Obstructive sleep apnea disease (OSA) is associated with a myriad of endocrine adverse effects. Changes in the serum prolactin (PRL) secretion in OSA are thought to be related to the hypoxic stress and subsequently to result in reversible changes with effective continuous positive airway pressure (CPAP) therapy. Due to current disagreements on this topic, we investigated the effect of CPAP therapy on the serum PRL in patients with OSA, using the most accurate CPAP compliance assessment to date Fourteen adults were recruited from those scheduled at the Salem Veterans Affairs Medical Center for a diagnostic polysomnogram (PSG). Fasting serum PRL, estradiol, follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone (Test), glucose, cortisol (Cor), and leptin levels were measured at 7 a.m., the morning after PSG, and again in ten of these patients, after 11-39 months of CPAP therapy. Compliance data, for both short-term (mean, 34 days) and long-term follow-up (mean, 304 days), were downloaded. Except PRL, no other hormone's serum level, including that of FSH, LH, Test, Cor, and Leptin, has changed significantly after the CPAP therapy. CPAP therapy is associated with a significant decrease in serum PRL levels.

Galactorrhea with metoclopramide use in the neonatal unit

We report a 3(1/2)-month-old infant with trisomy 21 presenting with galactorrhea in the neonatal intensive care unit (NICU). Endocrine work-up showed a high prolactin level (64.4 ng ml(-1)--normal: 0.5 to 30 ng ml(-1)). Cessation of therapy with metoclopramide (0.2 mg kg(-1) per dose q 6 h) resulted in the resolution of galactorrhea with a decrease in serum prolactin level (20.1 ng ml(-1)). We present this case to highlight this uncommon side effect of a commonly used medication in the NICU.

A Randomized, Crossover Comparison of Herbal Medicine and Bromocriptine Against Risperidone-Induced Hyperprolactinemia in Patients With Schizophrenia

Hyperprolactinemia is a common adverse effect that occurs as a result of antipsychotic therapies, which often results in discontinuation. Empirical evidence has shown that some herbal medicines have suppressive effects on prolactin (PRL) hyperactivities. This study was designed to compare the herbal preparation called Peony-Glycyrrhiza Decoction (PGD) with bromocriptine (BMT), a dopamine agonist widely used for PRL-secreting disorders, in the treatment of risperidone-induced hyperprolactinemia. Twenty schizophrenic women who were under risperidone maintenance treatment, diagnosed with hyperprolactinemia (serum PRL levels >50 mug/L), and currently experiencing oligomenorrhea or amenorrhea were selected for the study. Subjects were randomized to additional treatment with PGD (45 g/d) followed by BMT (5 mg/d) or BMT followed by PGD at the same doses for 4 weeks each, with an interval of 4-week washout period between 2 treatment sessions. The severity of psychotic symptoms, adverse events, serum PRL, estradiol, testosterone, and progesterone levels were examined at baseline and end point. Peony-Glycyrrhiza Decoction treatment produced a significant baseline-end point decrease in serum PRL levels, without exacerbating psychosis and changing other hormones, and the decreased amplitudes were similar to those of BMT (24% vs 21%-38%). Moreover, there was a significantly greater proportion of patients during PGD treatment than BMT treatment showing improvements on adverse effects associated with hyperprolactinemia (56% vs 17%, P = 0.037). These results suggest that the herbal therapy can yield additional benefits while having comparable efficacy in treating antipsychotic-induced hyperprolactinemia in individuals with schizophrenia.

In vivo and in vitro effects of chromium VI on anterior pituitary hormone release and cell viability

Hexavalent chromium (Cr VI) is a highly toxic metal and an environmental pollutant. Different studies indicate that Cr VI exposure adversely affects reproductive functions. This metal has been shown to affect several tissues and organs but Cr VI effects on pituitary gland have not been reported. Anterior pituitary hormones are central for the body homeostasis and have a fundamental role in reproductive physiology. The aim of this study was to evaluate the effect of Cr VI at the pituitary level both in vivo and in vitro. We showed that Cr VI accumulates in the pituitary and hypothalamus, and decreases serum prolactin levels in vivo but observed no effects on LH levels. In anterior pituitary cells in culture, the effect of Cr VI on hormone secretion followed the same differential pattern. Besides, lactotrophs were more sensitive to the toxicity of the metal. As a result of oxidative stress generation, Cr VI induced apoptosis evidenced by nuclear fragmentation and caspase 3 activation. Our results indicate that the anterior pituitary gland can be a target of Cr VI toxicity in vivo and in vitro, thus producing a negative impact on the hypothalamic-pituitary-gonadal axis and affecting the normal endocrine function.

The Impact on Clinical Practice of Routine Screening for Macroprolactin

Prolactin (PRL) normally circulates in part as a high-molecular-weight form termed big-big PRL, which is a complex of PRL with an anti-PRL IgG autoantibody known as macroprolactin. Many patients with hyperprolactinemia resulting from macroprolactin lack classic hyperprolactinemic symptoms. Macroprolactin has reduced bioactivity in vivo. The investigators, working over 5 years at a single center, routinely screened for macroprolactin using the method of polyethylene glycol precipitation. The study population were individuals whose serum PRL exceeded the upper limit of the normal reference range (500 mU/L for females, 290 mU/L for males). Elevated plasma PRL levels were found in 2089 individuals, representing 21% of all samples analyzed. A majority of these samples contained more than 700 mU/L of total PRL. More than one fifth (22%) of hyperprolactinemic samples were accounted for by macroprolactin. This was the case more often for females than for males. Those with mild hyperprolactinemia (total PRL of 700 mU/L or less) more often had macroprolactinemia, but the proportion of clinically significant hyperprolactinemic samples accounted for by macroprolactin was comparable at all levels of total PRL. There were no differences in frequency of headache or infertility between patients with true hyperprolactinemia and those with macroprolactinemia, but galactorrhea and oligomenorrhea were more frequent in the former group. Although scans were done in similar proportions of patients, abnormalities were found mainly in the hyperprolactinemic group. Treatment with a dopamine agonist decreased serum prolactin levels in both groups; 15 of 19 treated women having true hyperprolactinemia and galactorrhea improved symptomatically. Macroprolactinemic patients had significantly higher plasma levels of estradiol than did those with true hyperprolactinemia, although there was overlap between the groups. Levels of luteinizing hormone (LH) and the LH/follicle-stimulating hormone (FSH) ratio were significantly greater in macroprolactinemic patients. Macroprolactinemia is a common cause of elevated serum PRL. Routine screening of hyperprolactinemic individuals for macroprolactin may alter treatment in as many as one fifth of patients with hyperprolactinemia. Imaging is needed less often, as is dopamine agonist treatment, offsetting the added cost of screening and making the procedure cost-effective.

Lipopolysaccharide- and Tumor Necrosis Factor-α-Induced Changes in Prolactin Secretion and Dopaminergic Activity in the Hypothalamic-Pituitary Axis

Bacterial lipopolysaccharide (LPS) affects pituitary hormone secretion, including prolactin release, by inducing synthesis and release of cytokines such as tumor necrosis factor-α (TNF-α). Since prolactin is mainly under tonic inhibitory control of dopamine, we investigated the effect of LPS and TNF-α on the hypothalamic-pituitary dopaminergic system. LPS (100–250 µg/rat, i.p.) decreased serum prolactin levels after 1 or 3 h. Sulpiride, a dopaminergic antagonist, increased serum prolactin and blocked the inhibitory effect of LPS. LPS increased hypothalamic dopamine and DOPAC concentrations and the DOPAC/dopamine ratio both in mediobasal hypothalamus and the posterior pituitary. LPS also enhanced dopamine and DOPAC concentration in the anterior pituitary. LPS elevated plasma levels of epinephrine, norepinephrine and dopamine but it did not modify the concentration of epinephrine or norepinephrine in the tissues studied. The administration of TNF-α (i.c.v., 1 h, 100 ng/rat) decreased serum prolactin but did not affect plasma catecholamine levels. TNF-α did not modify the DOPAC/dopamine ratio in hypothalamus or posterior pituitary but increased dopamine and DOPAC concentrations in the anterior pituitary. Incubations of hypothalamic explants showed that TNF-α did not modify in vitro basal dopamine release and reduced K⁺-evoked dopamine release. On the contrary, incubations of posterior pituitaries showed that TNF-α significantly increased basal and K⁺-evoked dopamine release. These results indicate that LPS and TNF-α increase dopamine turnover in the hypothalamic-pituitary axis. This increase in dopaminergic activity could mediate the inhibitory effect of LPS and TNF-α on prolactin release. Furthermore, the increase in dopaminergic activity elicited by LPS could be mediated by an increase in hypothalamic TNF-α during endotoxemia.

Decreased serum prolactin levels associated with infections in female patients with symptoms of spontaneous abortion

Previous research indicates that intraocular infections result in dramatic decrease of prolactin serum levels during pregnancy. The aim of this study was to assess biochemical aspects of pregnancy, including determination of serum prolactin levels in patients with infection. The evaluation included patients with symptoms of imminent miscarriage and present, or absent signs of vaginal infection, as well as patients with uncompromised pregnancies, as controls. Serum estradiol levels, progesterone and prolactin were decreased in patients with bacterial infections. The role of prolactin in regulation of pregnancy was discussed, as well as its interactions with other regulatory hormones of pregnancy. Serum prolactin levels were decreased (17.68%) in patients with symptoms of imminent miscariage and current lower genital infection.