Concentrations Of Several Hormones Research Articles

Assessing the effects of ex vivo hormonal exposure on oxidative responses in equine leukocytes: A preliminary study

Breed differences exist between horses and ponies in circulating concentrations of several hormones, notably ACTH and insulin. These hormones regulate stress and metabolic responses, but in other species, they also impact leukocyte oxidant responses. The effects of these hormones on equine leukocytes have not been evaluated to date. If equine leukocytes are similarly regulated, breed differences in increased plasma hormone concentrations or altered sensitivity to them at the leukocyte level could result in breed-related differences in oxidant responses or oxidative status. The objective of this study was therefore to determine the effects of ex vivo exposure to adrenocorticotropic hormone (ACTH), α-melanocyte stimulating hormone (α-MSH), insulin, or leptin on reactive oxygen species (ROS) production from leukocytes isolated from horses and ponies. We hypothesized that ACTH, α-MSH, insulin, and leptin would alter oxidant responses from equine leukocytes in a breed specific manner. Blood was collected from 10 apparently healthy Quarter horses and seven Welsh ponies for isolation of neutrophils and peripheral blood mononuclear cells (PBMCs) via density gradient centrifugation. Cells were incubated with media (negative control), microbial antigens (positive control), or ACTH, α-MSH, leptin, or insulin for two hours. Induced ROS production was quantified with a previously validated fluorometric assay. Data was compared within groups by comparing a stimulant within a group (horses or ponies) to baseline, between groups by comparing horse response to pony response, and among stimulants using one- and two-way, repeated measures ANOVA (P<0.05). There was no significant effect of breed on basal, microbial-induced, or hormone-induced ROS production from neutrophils (P=0.465) or PBMCs (P=0.749), but in neutrophils, a significant interaction between breed and stimulant was present (P=0.037). ROS production from PBMCs from horses after hormone exposure did not differ from cells exposed to media only (P=0.1520–0.8180). Similarly, neither leptin nor insulin exposure significantly induced ROS production from PBMCs from ponies (P= 0.2645 and 0.4678 respectively), but exposure to ACTH or α-MSH induced a significant increase in ROS production (P=0.0441 and 0.0440 respectively) compared to unstimulated cells. Hormones that vary in availability among breeds may induce ex vivo pro-oxidant responses in equine leukocytes, but specific effects are breed-, leukocyte type-, and hormone-dependent. Breed differences in hormonally induced leukocyte ROS production may warrant further investigation in the context of circulating oxidative stress and how this might relate to future disease risk.

Additive effects of light and branching on fruit size and chemical fruit quality of greenhouse tomatoes.

Greenhouse tomato growers face the challenge of balancing fruit size and chemical quality traits. This study focused on elucidating the interplay between plant branching and light management on these traits, while maintaining consistent shoot density. We evaluated one- and two-shoot plants under varying top light intensities using high-pressure sodium lamps and light-emitting diode (LED) inter-lighting. The reduced yield in the two-shoot plants was mainly due to smaller fruit size, but not due to source strength limitations, as evaluated through leaf weight ratio (LWR), chlorophyll index, specific leaf area (SLA), leaf dry matter percentage, and stem soluble carbohydrate accumulation. Enhanced lighting improved fruit weight and various fruit traits, such as dry matter content, total soluble carbohydrate content, and phenolic content, for both one- and two-shoot plant types. Despite lower mean fruit weight, two-shoot plants exhibited higher values for chemical fruit quality traits, indicating that the fruit growth of two-shoot plants is not limited by the available carbohydrates (source strength), but by the fruit sink strength. Diurnal analysis of fruit growth showed that two-shoot plants had reduced expansion during light transitions. This drop in fruit expansion was not related to changes in root pressure (measured as xylem sap exudation from decapitated plants), but might be related to diminished xylem area in the stem joint of the two-shoot plants. The concentration of several hormones, including cytokinins, was lower in two-shoot plants, suggesting a reduced fruit sink capacity. The predominant impact of branching to two-shoot plants on sink capacity suggests that the fruit growth is not limited by available carbohydrates (source strength). Alongside the observation that light supplementation and branching exert independent additive effects on fruit size and chemical traits, this illuminates the potential to independently regulate these aspects in greenhouse tomato production.

The Effect of Leptin on the Blood Hormonal Profile (Cortisol, Insulin, Thyroid Hormones) of the Ewe in Acute Inflammation in Two Different Photoperiodical Conditions.

As a day animal with sensitivity to inflammation similar to that of humans, the sheep may highly outperform the rodent model in inflammation studies. Additionally, seasonality makes sheep an interesting model in endocrinology research. Although there are studies concerning inflammation’s influence on leptin secretion and vice versa, a ewe model, with its possible ‘long-day leptin resistance’, is still not examined enough. The present study aimed to examine whether leptin may modulate an acute inflammation influence on plasma hormones in two photoperiodical conditions. The experiment was conducted on 48 ewes divided into four groups (control, lipopolysaccharide (LPS), leptin, LPS + leptin) during short and long days. Blood sampling started 1 hour before and continued 3 h after LPS/saline administration for further hormonal analysis. The results showed that the photoperiod is one of the main factors influencing the basal concentrations of several hormones with higher values of leptin, insulin and thyroid hormones during long days. Additionally, the acute inflammation effect on cortisol, insulin and thyroid hormones was photoperiod-dependent. The endotoxemia may also exert an influence on leptin concentration regardless of season. The effects of leptin alone on hormone blood concentrations are rather limited; however, leptin can modulate the LPS influence on insulin or thyroxine in a photoperiod-dependent way.

Improvement of several stress response and sleep quality hormones in men and women after sleeping in a bed that protects against electromagnetic fields

BackgroundThe electromagnetic fields (EMFs) emitted by the technologies affect the homeostatic systems (nervous, endocrine, and immune systems) and consequently the health. In a previous work, we observed that men and women, after 2 months of using a bed with a registered HOGO system, that prevents and drain EMFs, improved their immunity, redox and inflammatory states and rejuvenated their rate of aging or biological age. Since, EMFs can act as a chronic stressor stimulus, and affect the sleep quality. The objective of this work was to study in men and women (23–73 years old) the effect of sleeping for 2 months on that bed in the blood concentrations of several hormones related to stress response and sleep quality as well as to corroborate the rejuvenation of their biological age.MethodsIn 18 men and women, plasma concentration of cortisol, dehydroepiandrosterone (DHEA), catecholamines (epinephrine, norepinephrine and dopamine), serotonin, oxytocin and melatonin were analyzed before and after 2 months of using the HOGO beds. A group of 10 people was used as placebo control. In another cohort of 25 men (20 experimental and 5 placebo), the effects of rest on the HOGO system on the concentration of cortisol and testosterone in plasma were studied. In all these volunteers, the biological age was analyzed using the Immunity Clock model.ResultsThere is a significant increase in plasma concentration of DHEA, norepinephrine, serotonin, oxytocin, and melatonin as well as in testosterone, after resting for 2 months in that bed with the EMFs avoiding system. In addition, decreases in Cortisol/DHEA and Testosterone/cortisol ratio and plasma dopamine concentration were observed. No differences were found in placebo groups. In all participants that slept on HOGO beds, the biological age was reduced.ConclusionsSleeping in a bed that isolates from EMFs and drain them can be a possible strategy to improve the secretion of hormones related to a better response to stress and sleep quality, which means a better endocrine system, and consequently better homeostasis and maintenance of health. This fact was confirmed with the slowdown in the rate of aging checked with a rejuvenation of the biological age.

Melatonin influences the early growth stage in Zoysia japonica Steud. by regulating plant oxidation and genes of hormones

Zoysia japonica is a commonly used turfgrass species around the world. Seed germination is a crucial stage in the plant life cycle and is particularly important for turf establishment and management. Experiments have confirmed that melatonin can be a potential regulator signal in seeds. To determine the effect of exogenous melatonin administration and explore the its potential in regulating seed growth, we studied the concentrations of several hormones and performed a transcriptome analysis of zoysia seeds after the application of melatonin. The total antioxidant capacity determination results showed that melatonin treatment could significantly improve the antioxidant capacity of zoysia seeds. The transcriptome analysis indicated that several of the regulatory pathways were involved in antioxidant activity and hormone activity. The hormones concentrations determination results showed that melatonin treatment contributed to decreased levels of cytokinin, abscisic acid and gibberellin in seeds, but had no significant effect on the secretion of auxin in early stages. Melatonin is able to affect the expression of IAA (indoleacetic acid) response genes. In addition, melatonin influences the other hormones by its synergy with other hormones. Transcriptome research in zoysia is helpful for understanding the regulation of melatonin and mechanisms underlying melatonin-mediated developmental processes in zoysia seeds.

Visual stimulation with food pictures in the regulation of hunger hormones and nutrient deposition, a potential contributor to the obesity crisis.

Food cues affect hunger and nutritional choices. Omnipresent stimulation with palatable food contributes to the epidemics of obesity. The objective of the study was to investigate the impact of food cues on appetite-related hormones and to assess the functionality of the secreted hormones on macronutrient uptake in healthy subjects. Additionally, we aimed at verifying differences in the response of total and active ghrelin to stimulation with food pictures and to a meal followed by the stimulation. We were also interested in the identification of factors contributing to response to food cues. We recruited healthy, non-obese participants for two independent cross-over studies. During the first study, the subjects were presented random non-food pictures on the first day and pictures of foods on the second day of the study. Throughout the second study, following the picture session, the participants were additionally asked to drink a milkshake. Concentrations of blood glucose, triglycerides and hunger-related hormones were measured. The results showed that concentrations of several hormones measured in the blood are interdependent. In the case of ghrelin and gastric inhibitory peptide (GIP) as well as ghrelin and glucagon-like peptide-1 (GLP-1), this co-occurrence relies on the visual cues. Regulation of total ghrelin concentration following food stimulation is highly individual and responders showed upregulated total ghrelin, while the concentration of active ghrelin decreases following a meal. Protein content and colour intensity of food pictures reversely correlated with participants' rating of the pictures. We conclude that observation of food pictures influences the concentration of several appetite-related hormones. The close link of visual clues to physiological responses is likely of clinical relevance. Additionally, the protein content of displayed foods and green colour intensity in pictures may serve as a predictor of subjective attractiveness of the presented meal.

Fake twins? Two cases of intensive allomaternal care by female Japanese macaques before and after their own partum.

Allomaternal care is widely observed among primate species. Although diverse allomothering behavioral repertoire and types of caretakers have been reported, it remains unclear what social or physiological conditions may trigger such care in each individual. For a better understanding of mechanisms that give rise to allomaternal care in primates, more observational reports are needed with information on social or physiological conditions of caretakers. Here I report two cases of intensive allomaternal care in two different populations of Japanese macaques (Macaca fuscata). The two adult females provided intensive allomaternal care including carrying, grooming, and nursing towards others' infants. Their allomaternal care began 20 or 29days prior to their own partum and lasted for 84days at the most. This study firstly showed that nursing forms part of the allomothering behavioral repertoire, and allomaternal caretakers can be individuals that are prior to the time of their own partum in Japanese macaques. Their intensive allomaternal care may stem from their good nutritional conditions, increased concentrations of several hormones, or disappearance of the newborn infants' biological mothers.

Visual stimulation with food pictures in regulation of hunger hormones and nutrient deposition

AbstractFood cues modulate hunger and dictate nutritional choices. The omnipresent stimulus of palatable food promotes the epidemics of obesity and metabolic diseases. The aim of our study was to investigate the impact of visual stimulation with food pictures on appetite-related hormones as well as the functionality of the secreted hormones and its impact on macronutrient uptake and deposition in healthy subjects. Additionally, we sought to identify differences in response to visual food cues of total and active ghrelin to and to a meal followed by the stimulation.Healthy, non-obese participants were recruited for two two-day studies. During the first study, the subjects were shown random non-food pictures on the first day and pictures of appetizing foods on the second day of the study. The second study followed the same schedule and additionally, following the picture session, the participants were asked to drink a milkshake. The subjects reported subjective hunger. Levels of glucose, triglycerides and hunger-related hormones were measured in blood. In addition, an animal study was performed, during which 4 hours fasted mice were submitted to visual and olfactory stimulation using chow, while not being able to access the food. Following the stimulation, oral glucose tolerance test was performed, gene expression and blood total, as well as acylated ghrelin, were measured.Exposure to food pictures affected participant's blood glucose and incretin levels. Concentrations of several hormones in the blood were interdependent and in case of ghrelin and GIP as well as ghrelin and GLP-1 this co-occurrence relied on the visual cues. Changes of total ghrelin concentration following food stimulation was highly individual and participants could be grouped as ghrelin responders or non-responders. The responders showed upregulated total ghrelin and their total ghrelin levels correlated with food picture score revealing that in ghrelin non-responders reaction to food pictures was diminished. The concentration of active ghrelin decreased following a meal but was not affected by exposure to the pictures of food. Protein content and color intensity of food pictures correlated reversely with participants’ rating of the pictures. Sensory stimulation of mice resulted in increased blood glucose levels.We conclude that observation of food pictures significantly influences blood glucose levels and concentration of several appetite-related hormones. The protein content of the observed foods and green color intensity in pictures may serve as a predictor of subjective attractiveness of the presented meal.

Hair as a Specimen to Determine the Concentration of Cortisol Levels in Individuals that have Performed Physical Activity

Introduction The physical inactivity has been identified as the fourth leading risk factor for mortality in the world. Physical activity may exert beneficial influence on the cardiovascular system, besides to bring benefits to the lipid metabolism, the increase of the lean mass, and the increase of the basal metabolism. As a response of the physical activity, the concentration of several hormones is altered, as the cortisol. Different specimens are used to determination of concentration of the cortisol, like saliva, urine, blood samples and hair. The aim of this narrative review is to present scientific information about the use of the hair to evaluate the concentration of cortisol in individuals that have performed physical activity. Materials and Methods Publications were accessed in the database PubMed September 12th, 2018 using the keywords hair and “physical activity” and cortisol. Results In general, it was found that the hair can be used to determine the concentration of cortisol in different populations. Conclusions In conclusion, all the considerations of this review, it is possible to conclude that the hair can be used successfully, as a specimen, to determine the concentration of the cortisol in the body. This would have an importance to verify the response of the hypothalamus-pituitary-adrenocortical axis to the physical activity.

Ketosis and appetite-mediating nutrients and hormones after weight loss

Diet-induced weight loss is accompanied by compensatory changes, which increase appetite and encourage weight regain. There is some evidence that ketogenic diets suppress appetite. The objective is to examine the effect of ketosis on a number of circulating factors involved in appetite regulation, following diet-induced weight loss. Of 50 non-diabetic overweight or obese subjects who began the study, 39 completed an 8-week ketogenic very-low-energy diet (VLED), followed by 2 weeks of reintroduction of foods. Following weight loss, circulating concentrations of glucose, insulin, non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHB), leptin, gastrointestinal hormones and subjective ratings of appetite were compared when subjects were ketotic, and after refeeding. During the ketogenic VLED, subjects lost 13% of initial weight and fasting BHB increased from (mean±s.e.m.) 0.07±0.00 to 0.48±0.07 mmol/l (P<0.001). BHB fell to 0.19±0.03 mmol/l after 2 weeks of refeeding (P<0.001 compared with week 8). When participants were ketotic, the weight loss induced increase in ghrelin was suppressed. Glucose and NEFA were higher, and amylin, leptin and subjective ratings of appetite were lower at week 8 than after refeeding. The circulating concentrations of several hormones and nutrients which influence appetite were altered after weight loss induced by a ketogenic diet, compared with after refeeding. The increase in circulating ghrelin and subjective appetite which accompany dietary weight reduction were mitigated when weight-reduced participants were ketotic.

159 EFFECTS OF EMBRYO TRANSFER IN A LARGER BREED ON POSTNATAL GROWTH AND GLUCOSE METABOLISM IN HORSES

In equids, the size of the uterus determines fetal intrauterine development, which in turn affects postnatal insulin sensitivity and growth rate. We induced intrauterine growth enhancement through embryo transfer using Pony (P), Saddlebred (S), and Draft (D) horses and studied growth and insulin sensitivity in foals from birth to one year of age. Control pregnancies of S-in-S (n = 14) and P-in-P (n = 10) were obtained by AI. Enhanced fetal growth was obtained by transferring S (S-in-D, n = 7) and P embryos (P-in-D, n = 5) into D mares. From birth to weaning (180 days), each foal was kept with its surrogate P, S, or D dam. At 3, 140, and 380 days, glucose clearance and pancreatic beta cell response to exogenous glucose were assessed with an intravenous glucose tolerance test (IVGTT). At 200 days, the euglycemic-hyperinsulinemic clamp method was used to determine the sensitivity and responsiveness of tissues to exogenous insulin. Plasma T3, T4, and IGF1 were assayed at 3 and 180 days. Data were analysed using one-way ANOVA and Tukey post hoc tests. S-in-S were heavier and taller than P-in-P from birth to 380 days (P &lt; 0.001). Before weaning, plasma concentrations of several hormones involved in growth were lower in S-in-S than P-in-P (at 3 and 180 days, respectively, T3: P = 0.08 and P = 0.02, T4: P &lt; 0.001 and P = 0.06, IGF1: P = 0.04 and P &lt; 0.001). No difference was found in glucose regulation between these groups. In contrast, post-weaning insulin resistance was observed in P-in-P at 200 days (P &lt; 0.001) and confirmed at 380 days where they exhibited slower glucose clearance (P = 0.03) associated with higher fasting glucose (P &lt; 0.001) than S-in-S. Fetal growth was not enhanced in S-in-D with no difference in height and weight at birth. Although S-in-D grew faster from 30 to 140 days, growth rates were not different from S-in-S after weaning, weaning coinciding with lower T3 (P &lt; 0.001) in S-in-D than in S-in-S. Glucose regulation was not different between the two groups, but insulin remains to be assayed at 140 and 380 days. Fetal growth was enhanced in P-in-D: at birth, they were heavier (P = 0.01) and taller (P &lt; 0.001) than P-in-P. Growth of P-in-D was faster until weaning. No more difference, however, was observed between P-in-D and P-in-P at 380 days. Plasma concentrations of T3 (P = 0.03) and those of T4 (P &lt; 0.001) were lower at 3 days and T3 was still lower at 180 days (P &lt; 0.001) in P-in-D compared with P-in-P. Moreover, P-in-D developed early insulin resistance: insulin secretion was higher in P-in-D compared with P-in-P (P = 0.002) after IVGTT at 3 days. At 200 days, however, P-in-D and P-in-P had the same sensitivity to insulin. There was no difference in glucose clearance rates at 380 days, but P-in-D had lower fasting glucose (P &lt; 0.001) than P-in-P. Insulin assays at 140 and 380 days are pending. In conclusion, these data indicate that transfer of a small breed embryo into a large breed mare and subsequent suckling by the recipient mare can enhance fetal and postnatal growth and affect the foal’s glycaemia and sensitivity to insulin at birth and in subsequent months. Ongoing work includes analyses of milk samples and effects on general health.

Adaptive changes of the indices of the cardiovascular system and serum content of a number of hormones under examination stress condition

Aim. To study the features of the indices of the cardiovascular system and serum concentrations of several hormones and biogenic amines among the students under the impact of examination stress. Methods. The study was conducted on a group of young conditionally healthy volunteers. The starting group of study subjects consisted of 203 students who prior to participation in the study passed a medical examination, including medical history, calculation of body mass index, physical, instrumental and laboratory investigations. As a result, 93 students were selected; their own indicators outside the examination period were used as controls. The study individuals had an investigation of the state of autonomic reactions (measurement of systolic and diastolic blood pressure, heart rate, Kerdo autonomic index) conducted 1 hour before and within 1 hour after the examination. The hormonal status was investigated by enzyme immunoassay. The results of the study were verified using the software package «StatPlus». Results. Sympathicotonic nature of the vegetative response dominated, according to which two categories of students were allocated: with a steady and significant increase in Kerdo autonomic index (53%) and with the lack of such growth rate (47%). In the study of the hormonal profile a reduction in the serum concentrations of thyroid-stimulating hormone and cortisol levels, an increase in blood content of the tested biogenic amines - histamine, epinephrine (adrenaline), serotonin was revealed. Conclusion. The established changes in the indices of the cardiovascular and endocrine systems emphasize the individual nature of each subject’s reactions, and therefore require clustering of students into groups according to the characteristics of autonomic and hormonal responses to psychoemotional stress.

LACTATION BIOLOGY SYMPOSIUM: Effects of photoperiod on mammary gland development and lactation1

Photoperiod, or the daily sequence of light and dark, has dramatic effects on many physiological systems across animal species. Light patterns alter melatonin secretion profiles and, subsequently, the release profiles and circulating concentrations of several hormones that influence a variety of physiological responses. Although the impact of photoperiod on reproductive processes is perhaps the most common example, it is often the seasonal aspects of ovulation and anestrus that are considered. However, in cattle, the final phase of reproduction, that is, lactation, is significantly influenced by photoperiod. In contrast to short days (SDPP; 8 h light:16 h dark), exposure to long days (LDPP) of 16 to 18 h of light and 6 to 8 h of darkness increases milk yield 2 to 3 kg/d, regardless of the stage of lactation. There is evidence that this LDPP effect is due to increased circulating IGF-I, independent of any effect on GH concentrations. Cows that are housed under SDPP during the dry period have increased mammary growth and produce 3 to 4 kg/d more milk in the subsequent lactation compared with cows on LDPP when dry. While cows are on SDPP, circulating prolactin (PRL) diminishes but expression of PRL receptor increases in mammary, liver, and immune cells. Moreover, PRL signaling pathways within those tissues are affected by photoperiod. Further, replacement of PRL to cows on SDPP partially reverses the effects of SDPP on production in the next lactation. Thus, effects on dry cows are mediated through a PRL-dependent pathway. Before maturity, LDPP improve mammary parenchymal accumulation and lean body growth, which lead to greater yields in the first lactation. The accumulated evidence supports the concept that photoperiod manipulation can be harnessed to improve the efficiency of production across the life cycle of the dairy cow.

Hyponatremia and Subarachnoid Hemorrhage: Will That Be One Pinch or Two of Salt?

Hyponatremia and Subarachnoid Hemorrhage: Will That Be One Pinch or Two of Salt?

A marker of growth differs between adolescents with high vs. low sugar preference

Sweet preference is higher in childhood than adulthood but the mechanism for this developmental shift is not known. The objective of this study was to assess perceptual, physiological and eating habit differences between children preferring solutions high in sugar (high preference) and children preferring solutions low in sugar (low preference). We tested 143 children (11- to 15-years old) using sip and spit methodology to assess their hedonic profile, detection threshold, and perceived intensity of sucrose. Their plasma concentration of several hormones, a biomarker of bone-growth, body size, puberty stage, and dietary habits were measured. Eighty-eight children were classified as high preference and 53 were classified as low preference based on their hedonic ratings to a series of sucrose solutions. A marker of bone growth measured in urine and plasma leptin adjusted for body weight were significantly lower in the low preference group. Children with high and low preference patterns did not differ in sensory aspects of sucrose perception, nor did they differ in age, body mass index percentile, or dietary restraint. The change in sugar preference from high to low during adolescence appears to be associated with the cessation of growth.

Hormonal and Psychobehavioral Predictors of Weight Loss in Response to a Short-Term Weight Reduction Program in Obese Women

Among the factors influencing weight loss and maintenance, psychobehavioral, nutritional, metabolic, hormonal and hereditary predictors play an important role. Psychobehavioral factors influence adherence to lifestyle changes and thus weight loss maintenance. The outcome of short-term weight reduction treatment is mainly affected by changes in energy and nutrient intake and physical activity and thus the impact of hormones can possibly be obscured. In order to reveal hormonal determinants of weight loss, a 4-week in-patient comprehensive weight reduction program was introduced in which food intake and physical activity were under the strict control. Women (n = 67, BMI: 32.4+/-4.4 kg; age: 48.7+/-12.2 years) who exhibited stable weight on a 7 MJ/day diet during the first week of weight management were given a hypocaloric diet yielding daily energy deficit 2.5 MJ over the subsequent 3-week period. This treatment resulted in a mean weight loss of 3.80+/-1.64 kg. Correlation analysis revealed that baseline concentrations of several hormones were significantly associated either with a higher (free triiodothyronine, C-peptide, growth hormone, pancreatic polypeptide) or with a lower (insulin-like growth factor-I, cortisol, adiponectin, neuropeptide Y) reduction of anthropometric parameters in response to weight management. In a backward stepwise regression model age, initial BMI together with baseline levels of growth hormone, peptide YY, neuropetide Y and C-reactive protein predicted 49.8 % of the variability in weight loss. Psychobehavioral factors (items of the Eating Inventory, Beck Depression score) did not contribute to weight change induced by a well-controlled short-term weight reduction program.

Physical activity and inactivity in relation to sex hormone, prolactin, and insulin-like growth factor concentrations in premenopausal women

An association between physical activity and premenopausal breast cancer risk may be due, in part, to relationships with sex hormones or growth factors. Therefore, we assessed whether MET-h/week of total physical activity (moderate-to-vigorous intensity), walking, or vigorous physical activity, and h/week of standing or sitting were associated with plasma concentrations of several hormones. We examined levels of estrogens, androgens, progesterone, prolactin, sex hormone binding globulin (SHBG), insulin-like growth factor-1 (IGF-1), IGF binding protein-3, and growth hormone (GH) in 565 premenopausal women, ages 33-52 years, from the Nurses' Health Study II (NHSII). About 87% of women had both timed follicular and luteal samples; other women had one untimed sample. In general we observed few associations between sex hormone or IGF levels and measures of physical activity or inactivity. However, free testosterone was modestly inversely associated with total physical activity (p-trend = 0.02). Luteal estradiol, free estradiol, and estrone also were inversely associated with total physical activity (p-trend = 0.10, 0.04, 0.01, respectively); however, the trend was substantially attenuated when excluding women with anovulatory cycles or irregular cycles. These cross-sectional results suggest that physical activity and inactivity have limited associations with premenopausal sex hormone and growth factor levels, except possibly luteal estrogens.

Maternal Serum Concentrations of Several Hormones in Does Bearing Different Fetal Number

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Thyroid hormones may influence the slow component of VO(2) in professional cyclists.

We analyzed the relationship between the plasma concentrations of several hormones (testosterone [T], follicle-stimulating [FSH] and luteinizing hormone [LH], cortisol [C], 3,5,3'-triiodothyronine [T(3)], thyroxine [T(4)], and thyrotrophin [TSH]) and the magnitude of the VO(2) slow component (Delta VO(2)) in a group of nine professional road cyclists (26+/-2 years). The resting levels of the aforementioned hormones were determined before the subjects performed a 20-min cycle ergometer test at approximately 80% of VO(2 max) (or approximately 400 W). Plasma concentrations of T(3) and T(4) were inversely correlated (p<0.05) with Delta VO(2) (r=-0.72 and rr=-0.66, respectively), suggesting, at least partly, and association between thyroid basal function and the VO(2) slow component of euthyroid elite endurance athletes during constant-load intense exercise.

WITHIN-PATIENT VARIABILITY OF HORMONE AND CYTOKINE CONCENTRATIONS IN HEART FAILURE

Several studies on disease and treatment effects on neurohormones have been conducted with small numbers of patients, using one blood sample as representative of their states. The aim of this study was to assess the within-patient variability of plasma concentrations of several hormones and cytokines of recent interest, in patients with moderate heart failure and controlled stable background therapy over 3 weeks. Blood for neurohormone and cytokine assays was sampled in duplicate from 18 patients with moderate heart failure. After an initial visit, the patients were kept on stable therapy until the second blood sampling 21±3 days later. The plasma concentrations of several neurohormones (endothelin, renin, angiotensin II, aldosterone, norepinephrine) and cytokines (interleukin-6 (IL-6), interleukin-13 (IL-13), ciliary neurotrophic factor (CNTF), leukemia inhibitory factor (LIF) and soluble receptor type I of tumour necrosis factor-α (sTNF-RI) were measured with immunochemical methods. Some cytokines (IL-13, CNTF and LIF) were not detected. Despite clinically satisfactory ACE inhibition, circulating angiotensin II and aldosterone levels were still elevated in some patients, suggesting aldosterone escape. The between-visit agreement of plasma concentrations measured in duplicate was less than 35% for all circulating factors, except renin which showed a higher variability throughout the 3-week study period.