High Prolactin Research Articles

The relation of serum prolactin levels and Toxoplasma infection in humans.

BackgroundToxoplasma gondii is an intracellular protozoan parasite distributed worldwide. Although the infection is benign in immunocompetent individuals, it is life threatening and complicated in immunocompromised patients and fetuses of pregnant women who received their first exposure to T. gondii during the pregnancy. Prolactin (PRL) is a hormone that is secreted by the pituitary gland, and it is confirmed that it plays a role in the immune system. The present study was carried out to assess the possible relation between serum PRL levels and Toxoplasma infection frequency in human.MethodsIn this cross-sectional study, 343 serum samples (240 from women and 103 from men) were collected from individuals who were referred for PRL checking in laboratories of Karaj, Iran. Blood samples were collected, and sera were separated and analyzed for the detection of anti-Toxoplasma IgG antibody by ELISA method. The levels of PRL were measured by Roche Elecsys 2010 analyzer, electrochemiluminescence technology.ResultsOf 343 sera, 110 samples (32%) consisting of samples from 42 men and 68 women had anti-T. gondii IgG antibody. The prevalence of T. gondii infection in women with high PRL levels was lower than that in the comparison group with normal levels of PRL and the relationship between these two parameters was statistically significant (P=0.016). In women with hyperprolactinemia, by increasing of PRL levels, the prevalence of T. gondii infection was reduced.ConclusionThe results of the current study confirmed the previous studies based on immunoregulatory role of PRL and indicated that high levels of PRL could be related to Toxoplasma seronegativity in women.

Clinical and Radiographic Characteristics Related to Hyperprolactinemia in Nonfunctioning Pituitary Adenomas

Hyperprolactinemia in patients with nonfunctioning pituitary adenomas (NFPAs) has been explained by the stalk compression of large pituitary adenomas. However, not all large NFPAs are associated with high serum prolactin levels. We aimed to elucidate and compare clinical, hormonal, and radiographic characteristics of NFPAs with and without hyperprolactinemia. We included 201 patients with clinically NFPAs who underwent transsphenoidal surgery performed by a single surgeon during 2010-2017 at a single center in Korea. We measured the three-dimensional diameters (anteroposterior [AP], width, height) and volumes of NFPA on magnetic resonance imaging. We conducted morning basal hormone measurements and dynamic tests preoperatively and 3 months postoperatively. All NFPAs were macroadenomas, and mean tumor volume was 10.4 ± 7.7 cm3. Of 201 patients, 59 (29.4%) had preoperative hyperprolactinemia. Hormone recovery rate was higher in patients with hyperprolactinemia compared with patients without hyperprolactinemia after age, sex, body mass index, tumor volume, and gross total resection adjustments (odds ratio [95% confidence interval]: 2.55 [1.10-5.92]). Tumor width/AP diameter ratio positively correlated with serum prolactin levels (r= 0.186, P= 0.008). Tumor volume was not significantly different between the 2 groups. Preoperative prolactin level is a useful marker to predict hormone recovery after surgery. Patients with NFPA and hyperprolactinemia tended to have a higher width/AP diameter ratio. Hyperprolactinemia of NFPA is more likely affected by tumor growth pattern, such as width/AP diameter ratio, than tumor volume.

Prolactin as immune cell regulator in Toxocara canis somatic larvae chronic infection.

Toxocariasis is a zoonotic disease produced by ingestion of larval Toxocara spp. eggs. Prolactin (PRL) has been considered to have an important role in Toxocara canis infection. Recent evidence has found that PRL directly can increase parasite growth and differentiation of T. canis. The present study, evaluated the effect of high PRL levels on the immune system’s response and parasites clearance in chronic infection. Our results showed that hyperprolactinemia did not affect the number of larvae recovered from several tissues in rats. Parasite-specific antibody production, showed no difference between the groups. Lung tissue presented eosinophilic granulomas typical of a chronic infection in all the experimental groups. Flow cytometry analysis was made in order to determine changes in the percentage of innate and adaptive immune cell subpopulations in the spleen, peripheric (PLN) and mesenteric (MLN) lymphatic nodes. The results showed a differential effect of PRL and infection on different immune compartments in the percent of total T cells, T helper cells, T cytotoxic cells, B cells, NK cells, and Tγδ cells. To our knowledge, for the first time it is demonstrated that PRL can have an immunomodulatory role during T. canis chronic infection in the murine host.

Granulomatous mastitis: etiology, imaging, pathology, treatment, and clinical findings.

To outline the demographics, clinical presentation, imaging features, and treatment modalities observed among a series of patients diagnosed with biopsy-proven granulomatous mastitis (GM). Following approval by institutional review board, retrospective chart review was performed on patients with biopsy-proven granulomatous mastitis at our institution in the period from January 2013 until October 2017. A total of 90 patients were identified: 87 women and 3 men. The mean age was 35years, mostly women in their reproductive age. In our study, patients with GM were more likely to be Hispanic compared to the general population. Sixty-three percent of patients were within 5years of previous pregnancy. Painful palpable mass-like lesion was the most common physical finding. Breast ultrasound (US) was performed in all patients, and most commonly showed a hypoechoic irregular-shaped mass. Mammography (MG) showed asymmetry or irregular mass as the main finding. Definitive diagnosis was obtained by imaging-guided core needle biopsies in 94.4%. Conservative management was preferred, and only one patient underwent surgery. Although clinical and radiological findings of patients with GM may mimic those of breast carcinoma, our study showed that women of childbearing age, especially among Hispanic ethnicity with a recent history of pregnancy or high prolactin level and newly tender mass-like lesion, in addition to new focal asymmetry on mammogram and heterogeneous hypoechoic irregular-shaped mass on ultrasound exam, should raise concern for GM. Non-invasive approach and clinical follow-up were the preferred treatment method.

Influence of prolactin and estrogen on disease activity in patients with systemic lupus erythematosus

ObjectiveThe objective of this paper is to evaluate the role of prolactin and estrogen levels on disease activity in patients with systemic lupus erythematosus (SLE).Patients and methodsThis study included 60 female patients with SLE, with a mean age of 33.5±13.12 years. It was conducted between November 2014 and October 2015. Disease activity was defined according to Systemic Lupus Erythematosus Activity Index; score of at least 6 was considered as an active disease. Prolactin (PRL) and estrogen levels and other serological markers of lupus disease activity, namely, complement 3,4 (C3 and C4), erythrocyte sedimentation rate, C-reactive protein, and anti-double-stranded DNA (anti-dsDNA) titer were calculated.ResultsHyperprolactinemia was present in 25.0% of patients, and low estrogen level was present in 33.3% of patients. There was no significant correlation between either of estrogen or prolactin levels and all clinical and laboratory features, except for a significant positive correlation between anti-dsDNA and hyperprolactinemia.ConclusionThere was no significant correlation between either of PRL or estrogen levels and Systemic Lupus Erythematosus Activity Index score. Overall, 80.0% of patients with hyperprolactinemia and 80.0% with low estrogen level had SLE activity. There was a significant difference in the frequency of further indicators of disease activity in SLE such as raised erythrocyte sedimentation rate, raised C-reactive protein, or decrease in complement factors with high serum PRL and low estrogen level.

Serum prolactin level in chronic urticaria: Is bromocriptine inducing remission in chronic urticaria?

Background: Chronic urticaria (CU) is a disturbing disease with a negative impact on quality of life. Despite of several clinical studies on CU patients, its pathogenesis is poorly understood. Prolactin (PRL) is peptide hormone has immunomodulatory effects in some immune inflammatory skin diseases.Aim: To elucidate any possible relationship between the immunomodulatory effects of PRL and CU. Besides, the study aims to investigate the crucial role of antiprolactin drugs in the management of CU patients.Patients and methods: The serum PRL level of 40 female patients with CU was measured using the electrochemiluminescence immunoassay. The activity of CU was assessed by European Academy of Allergology and Clinical Immunology; Global Allergy and Asthma European Network; European Dermatology Forum (EAACI/GA2LEN/EDF) activity score. Patients with high PRL level had been given anti prolactin therapy to normalize their PRL levels. Then, the disease activity was reassessed in these patients.Results: The serum PRL level was high in 8 of 40 (20%) patients (43.18 ± 12.81). Half of patients with high PRL level had remission after treatment of hyperprolactinemia (p = .001).Conclusions: Serum PRL levels could not be considered as a marker of the disease activity in CU patients.

Very high prolactin levels associated to domperidone therapy

Very high prolactin levels associated to domperidone therapy

PMH25 - Reduced Risk of Hyperprolactinemia Among Patients Treated With Atypical Antipsychotics That Are Associated with Low or No Prolactin Elevation

To compare the risk of hyperprolactinemia among patients receiving atypical antipsychotics (AAs). METHODS Commercially insured adults aged 18 to 64 who received AAs (all AAs were considered) were identified from Truven Commercial US claims data (2006Q1–2016Q3). Two mutually exclusive cohorts were identified based on whether patients received AAs with a mechanism of action associated with no/low prolactin elevation (Low Prolactin Cohort) or moderate/high prolactin elevation (High Prolactin Cohort). For each AA treatment episode, patients were observed from start to end of treatment with the same AA. All AA treatment episodes (defined by gaps ≥180 days or AA change) were analyzed. Entropy balancing was used to reweight treatment episodes, so that the two cohorts have similar demographics, comorbidities, and mental health-related medical services. Risk of hyperprolactinemia was compared between cohorts using logistic-regression models. Analyses were replicated in Medicaid-insured patients. Among commercially insured patients, 446,673 and 77,532 AA treatment episodes were identified in the Low and High Prolactin cohorts. The mean treatment episode duration was 8 and 7 months in the Low and High Prolactin cohorts. The most commonly used AAs were quetiapine, aripiprazole, and olanzapine in the Low Prolactin Cohort, and risperidone, asenapine, and paliperidone in the High Prolactin Cohort. The prevalence of hyperprolactinemia while on treatment was 0.06% and 0.31% in the Low and High Prolactin cohorts. The odds of hyperprolactinemia in the Low Prolactin Cohort was 5 times lower than that in the High Prolactin Cohort (odds ratio=0.21; p<0.001). Similarly, the odds of hyperprolactinemia in the Low Prolactin Cohort (N=177,379) was 4 times lower than that in the High Prolactin Cohort (N=58,447) in Medicaid-insured patients (odds ratio=0.26; p<0.001). AAs associated with no/low prolactin elevation reduce the risk of hyperprolactinemia by up to 80% and may be considered in treatment decision-making to reduce the hyperprolactinemia burden in AA-treated patients.

S219. RISK FACTORS FOR LOW BONE MINERAL DENSITY IN PATIENTS TAKING ANTIPSYCHOTICS

BackgroundThe aim of this study is to explore potentially modifiable risk factors for low bone mineral density (BMD) in adults with psychotic disorders. Furthermore, we sought to identify gender-specific risk factors.MethodsThe study included 285 community-dwelling patients with psychotic disorders. Dual-energy x-ray absorptiometry was used to measure BMD. Laboratory examinations included vitamin D and prolactin levels. Low BMD was defined as<1 standard deviation below the mean for young adults. Clinical characteristics associated with low BMD were identified with logistic regression analysis in total population and each gender.ResultsFifty-eight (20.4%) subjects had low BMD. Low BMD was more common in men and in patients with low body mass indices (BMIs), as well as in those with shorter treatment durations, those on Medicaid, and patients using serotonergic antidepressants. Logistic regression analysis revealed that low BMD was negatively associated with BMI and treatment duration and positively with gender (male) and serotonergic antidepressants use in the overall population. In men, low BMD was associated with treatment duration and BMI; in women, low BMD was associated with BMI, prolactin level, vitamin D, and serotonergic antidepressant use.DiscussionLow BMI was risk factor for reduced BMD in both genders. Shorter treatment duration was associated with low BMD in men, whereas higher prolactin levels, lower vitamin D, and the use of serotonergic antidepressants were associated with low BMD in women. Psychotropic agents should be prescribed mindful of their effects on bone, as use of these medications is a modifiable risk factor for osteoporosis in women with psychotic disorders.

Cabergoline versus bromocriptine for the treatment of giant prolactinomas: A quantitative and systematic review.

The aim of this study is to compare the efficacy of bromocriptine (BRC) versus cabergoline (CAB) in patients with giant prolactinomas. We searched MEDLINE, EMBASE, CENTRAL and Clinical Trials.gov for studies dated before March 1st, 2016, that used BRC or CAB for the treatment of patients with giant prolactinomas. Specific eligibility criteria were set to identify articles and cases. The selected articles were reviewed, and the data were extracted for analysis. The compared outcomes included tumor shrinkage, tumor response, normalization of prolactin (PRL) level, and visual field defect (VFD) improvement. Gender differences were also considered. Differences between the groups were assessed using Student's t test and the chi-square test. Two hundred and forty-five records were identified, and 10 articles and 104 cases met the inclusion criteria. Based on our analysis, CAB is significantly better than BRC in normalizing PRL levels in patients, especially males, with giant prolactinomas (69.4% versus 31.7%, p = 0.01). However, there was no significant difference between the two drugs in terms of tumor shrinkage, tumor response and VFD improvement (p > 0.05) in male or female patients. CAB exhibits significantly better efficacy than BRC in the normalization of PRL levels in male patients with giant prolactinomas. Regarding tumor reduction and VFD improvement, both drugs are comparably effective for patients of both genders. This quantitative and systematic review provides preliminary evidence in favor of CAB as a medical therapy for treating giant prolactinomas in male patients, especially those with extremely high PRL levels.

Why do endocrine profiles in elite athletes differ between sports?

BackgroundEndocrine profiles have been measured on blood samples obtained immediately post-competition from 693 elite athletes from 15 Olympic Sports competing at National or International level; four were subsequently excluded leaving 689 for the current analysis.MethodsBody composition was measured by bioimpedance in a sub-set of 234 (146 men and 88 women) and from these data a regression model was constructed that enabled ‘estimated’ lean body mass and fat mass to be calculated on all athletes. One way ANOVA was used to assess the differences in body composition and endocrine profiles between the sports and binary logistical regression to ascertain the characteristic of a given sport compared to the others.ResultsThe results confirmed many suppositions such as basketball players being tall, weightlifters short and cross-country skiers light. The hormone profiles were more surprising with remarkably low testosterone and free T3 (tri-iodothyronine) in male powerlifters and high oestradiol, SHBG (sex hormone binding globulin) and prolactin in male track and field athletes. Low testosterone concentrations were seen 25.4% of male elite competitors in 12 of the 15 sports and high testosterone concentrations in 4.8% of female elite athletes in 3 of the 8 sports tested. Interpretation of the results is more difficult; some of the differences between sports are at least partially due to differences in age of the athletes but the apparent differences between sports remain significant after adjusting for age. The prevalence of ‘hyperandrogenism’ (as defined by the IAAF (International Association of Athletics Federations) and IOC (International Olympic Committee)) amongst this cohort of 231 elite female athletes was the highest so far recorded and the very high prevalence of ‘hypoandrogenism’ in elite male athletes a new finding.ConclusionsIt is unclear whether the differences in hormone profiles between sports is a reason why they become elite athletes in that sport or is a consequence of the arduous processes involved. For components of body composition we know that most have a major genetic component and this may well be true for endocrine profiles.

Frequency of Macroprolactin in Hyperprolactinemia.

To determine the frequency of Macroprolactin (MaPRL) in patients with increased total prolactin and its clinical and financial impact. Cross-sectional study. Section of Clinical Chemistry, Department of Pathology and Laboratory Medicine, The Aga Khan University Hospital, Karachi, from March to May 2015. Patients with high total prolactin were screened by polyethylene glycol (PEG) precipitation for determination of MaPRL. Clinical history, imaging work-ups, and cost incurred in further investigations were collected by telephonic interview after verbal consent. Patients were stratified into true hyperprolactinemia and macroprolactinemia after PEG treatment, based on monomeric prolactin levels. Medical records of cases registered with AKUH were reviewed to confirm the diagnosis. Two hundred and thirty-nine patients were identified with high prolactin levels. Macroprolactinemia was identified in 145 (60.7%) and true hyperprolactinemia in 94 (39.3%) patients. Galactorrhea was significantly more in true hyperprolactinemic females (p=0.022), followed by visual disturbances (p=0.01) and headache (p=0.006). Moreover, as majority of population were females, the clinical features in the macroprolactinemia group as compared to true hyperprolactinemic group were mostly related to non-pituitary causes like drug intake [42.5% (54) vs. 37% (30)], heat intolerance due to thyroidal illness [41.7% (53) vs. 38.3% (31)] and surgery [26.8% (34) vs 22.2% (18)] in females. Further radiological workup (MRI, CT) were conducted in 35 (37.2%) patients with true hyperprolactinemia. Twenty-one (60%) of the patients were confirmed to have pituitary adenomas. In eight (5.5%) patients with MaPRL, only one had pituitary microadenoma on radiological workup. Total cost impact on the basis of investigations, was significantly higher in the group undergone imaging, despite 7 out of 8 individuals found to have normal imaging results. The median total cost in true hyperprolactinemic group undergone imaging was Rs. 4370 (IQR=2412.5, 22850) as compared to macroprolactinemic groups; Rs. 3,250 (IQR=2150, 4278). There was significant difference in the cost burden of both the groups (p <0.001). High frequency of MaPRL was identified in patients with hyperprolactinemia. Screening with PEG precipitation in hyperprolactinemic sera is simple and cost-effective.

Are All High Blood Prolactin Levels Pathological?

Are All High Blood Prolactin Levels Pathological?

Hormonal profile of some infertile women in bida Nigeria

Background and Aim: The desire for reproduction is a basic human instinct, and it is well known that infertility is one of the psychosocial problems affecting many couples worldwide. The aim of this study is to evaluate the hormonal profile of infertile women in Bida metropolis. Materials and Methods: A total of 200 individuals comprising of 160 infertile and 40 fertile women as controls were recruited into this cross-sectional study in Bida metropolis, Nigeria. Serum luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin (PRL), progesterone, and estradiol were determined using enzyme immunosorbent assay. Results: Infertile women had significantly higher LH and PRL level (P 0.05) when compared to fertile women. Nonmenstruating women (NMW) had lower FSH and progesterone level (P 0.05) when compared to MW. Hormonal abnormalities were observed in 83.3% of the infertile women. This comprises of 30% secondary hypogonadism, 20% hyperprolactinemia/hypogonadism, 13.3% primary hypogonadism, 13.3% hyperestrogenemia, and 6.7% hyperprolactinemia. Conclusion: This study has shown that infertility remains a major problem affecting women of childbearing age. It is therefore recommended that couples should seek medical care on time as well as determine their hormonal status to correct any abnormality that might have arisen.

Klebsiella Meningitis as the Initial Presentation of Macroprolactinoma: A Case Report

Introduction: Gram negative bacterial meningitis is a rare initial presentation of a macroprolactinoma. Meningitis in these cases is likely caused by a defect in the sellar floor from surgical manipulation or treatment with a dopamine agonist causing rapid shrinkage of a tumor. Patients generally have headaches as the predominant symptom. Our case is an illustration of where meningitis is caused by a transsphenoidal surgery and where meningitis is the presenting symptom to diagnosing a macroprolactinoma.Case presentation: The patient is a 20-year old African female with history of transsphenoidal surgery over one year ago, who presents with headache associated with subjective fevers, nausea, and vomiting. The patient states that she had similar headaches for the past 2 years but not to this severity. She reports that when she was in her country one year ago she had an unknown surgery through her nose that helped the headaches for a short period of time. She recalls having increasingly irregular periods over the past year and milky discharge from her breasts.Results: Physical exam was significant for nuchal rigidity. CT scan showed large sellar mass and MRI was consistent with likely pituitary adenoma. The patient’s presentation was suspicious for meningitis, so a lumbar puncture was performed, and CSF analysis was consistent with bacterial meningitis. The patient was started on broad spectrum antibiotics until CSF cultures returned showing Klebsiella pneumoniae sensitive to ceftriaxone. Further testing showed very high prolactin levels. Endocrinology was consulted and agreed the tumor was a pituitary macroadenoma, most likely a prolactinoma due to her laboratory findings and symptoms of menstrual irregularity and galactorrhea. The patient was treated with Cabergoline 0.5 mg two times per week.Conclusion: Bacterial meningitis, especially when caused by gram negative organisms is a rare presentation of a pituitary macroprolactinoma. Thorough history taking, and prompt diagnostic evaluation is crucial, especially when medical records cannot be obtained. Treatment of both conditions quickly and simultaneously is important. The case also illustrates that how treating a prolactinoma can result in complications such as meningitis not just immediately after surgery but in any stage of treatment.

Sex differences in the relationship between prolactin levels and impaired processing speed in early psychosis.

Hyperprolactinaemia is commonly observed in people with psychotic disorders due to D2 receptor blockade by antipsychotic drugs, although it may also exist in drug-naïve patients with first-episode psychosis. Recent studies suggest that hyperprolactinaemia may have a negative impact on cognitive function in people with early psychosis. We aimed to explore whether there are sex differences in the association between prolactin levels and cognitive performance in early psychosis patients. We studied 60 young patients with early psychosis (aged 18-35 years, 35% females) and a sex- and age-matched control group of 50 healthy subjects. Cognitive assessment was performed with the MATRICS Consensus Cognitive Battery. Prolactin, total cortisol, follicular-stimulating hormone, luteal hormone and sex steroids (testosterone in men, oestradiol and progesterone in women) were measured in plasma. Salivary cortisol was measured at different sampling times (awakening response, 10:00 and 23:00). Psychopathological status was assessed, and antipsychotic treatment was registered. Multiple linear regression analyses were used to explore the relationship between prolactin and cognitive tasks while adjusting for covariates. Prolactin levels were associated with impaired processing speed in men, and this association was independent of cortisol and testosterone. In women, prolactin levels were not associated with processing speed tasks, although we observed a negative effect of prolactin on verbal learning and spatial working memory in female healthy subjects. The male-dependent effect maintained its significance after adjusting for education status, antipsychotic treatment and negative symptoms. Our study demonstrates that the previously reported association between high prolactin levels and impaired cognitive processes in early psychosis is restricted to men.

High prolactin concentration during lactation period induced disorders of maternal behavioral in offspring

Early-life stress during the perinatal period induces several neuropsychological disorders in adulthood. In animal studies, early-life stress during the perinatal period induces not only behavioral disorders but also other neurofunctional disorders, such as somatosensory functional disorder in adulthood. Furthermore, the offspring of an early-life-stressed parent also show disturbance of brain function in humans. Behavioral and neurological alterations in the offspring of a stressed parent have also been shown in animal studies. However, the mechanisms underlying such behavioral/neurological alterations are not yet fully understood. In this study, we found a disorder of maternal behavior in the offspring of early-life-stressed mothers. The stressed mothers showed high concentrations of serum prolactin (PRL) during pregnancy and lactation. The concentration on the day of weaning the offspring significantly correlated with the changes in the concentration of corticosterone and the neurological function of offspring. These findings indicate that PRL may be involved in the induction of transgenerational effects of early-life stress on the brain function of offspring. In addition, maternal PRL can be a good biomarker for predicting the potential risk of neurofunctional alterations in the offspring.

Study on the mechanism of Bushen Culuan Chongji treating "kidney deficiency and blood stasis" in ovulatory dysfunctional infertility

Kidney deficiency and blood stasis is the main cause of ovulatory dysfunctional infertility. Kidney deficiency is the main pathological mechanism. Blood stasis is the main pathological manifestation, and it is an important factor throughout. Bushen Culuan Chongji is under the guidance of traditional Chinese medicine(TCM) theory, previous years of clinical experience, combined with the etiology and pathogenesis of anovulatory infertility and modern pharmacological research results, selected, not only maintains the TCM syndrome differentiation and different diseases features, but also reflects the superiority of the combination of disease. In the study of Bushen Culuan Chongji in the treatment of anovulatory infertility, there was no acute toxicity and no LD50 was detected. No adverse effects and side effects were found in the reproductive, genetic, toxicity, teratogenic, and perinatal tests in their high and low dose groups. In pharmacodynamics experiments, it can promote the development and maturation of follicles and the formation of corpus luteum in rats. Taking the kidney deficiency and blood stasis syndrome as the breakthrough point, systematically study the efficacy, safety and mechanism of six ovulatory dysfunctional infertility diseases, including abnormal uterine bleeding-ovulatory disorders, polycystic ovary syndrome, high prolactin, luteinized unruptured follicle syndrome, luteal phase defect and diminished ovarian reserve/premature ovarian failure. It verified the contribution degree of reinforcing kidney and resolving stasis TCM, reflected the characteristics of combination between disease differentiation and syndrome differentiation, interpreted the treatment principles of treating different diseases with the same method, and provided scientific basis for clinical treatment.

Concentrations of Hormones During the Mid-Incubation Period in Kleptoparasitic and Honest Common Terns Sterna hirundo

Kleptoparasitism is a well-known foraging strategy used by many colonial seabirds. The expression of this behavior can reduce the cost of foraging during the breeding season and ultimately this can be reflected in physiological parameters. Here we analyzed the relationship between the trophic strategy of Common Terns Sterna hirundo and two hormones, that are known to be involved in decision-making during the reproductive cycle and foraging activities: corticosterone (CORT) and prolactin (PRL). The study was conducted during the breeding seasons 2012–2014 at the Banter See colony in northern Germany where individuals with different foraging strategies were identified and monitored since 2008. We studied the concentration of hormones in two groups of birds: kleptoparasitic individuals i.e. individuals who steal the food captured by another individual, and honest individuals i.e. individuals who obtain the food on their own. Blood samples were obtained during the mid-incubation period using a non-invasive technique. Both hormones showed no significant relationship to each other. CORT concentration was similar in both groups of birds. However, the concentration of PRL was higher in parasitic than honest individuals in 2014. In addition, CORT modelling indicated a year effect (higher CORT in 2013), and PRL modelling indicated a significant effect of year (higher PRL in 2012) and a significant interaction between year and the trophic strategy in 2014. The results show no clear relationship between the feeding strategy and studied corticosterone and prolactin levels.

Auditory closed-loop stimulation of EEG slow oscillations strengthens sleep and signs of its immune-supportive function

Sleep is essential for health. Slow wave sleep (SWS), the deepest sleep stage hallmarked by electroencephalographic slow oscillations (SOs), appears of particular relevance here. SWS is associated with a unique endocrine milieu comprising minimum cortisol and high aldosterone, growth hormone (GH), and prolactin levels, thereby presumably fostering efficient adaptive immune responses. Yet, whether SWS causes these changes is unclear. Here we enhance SOs in men by auditory closed-loop stimulation, i.e., by delivering tones in synchrony with endogenous SOs. Stimulation intensifies the hormonal milieu characterizing SWS (mainly by further reducing cortisol and increasing aldosterone levels) and reduces T and B cell counts, likely reflecting a redistribution of these cells to lymphoid tissues. GH remains unchanged. In conclusion, closed-loop stimulation of SOs is an easy-to-use tool for probing SWS functions, and might also bear the potential to ameliorate conditions like depression and aging, where disturbed sleep coalesces with specific hormonal and immunological dysregulations.