Blood Hormone Concentrations Research Articles

Systematic review and meta-analysis of the baseline concentrations and physiologic responses of gut hormones to food in eating disorders

Background: Disturbances in gastrointestinal hormones have been widely identified in persons with eating disorders (EDs) and have been implicated in their clinical pathologies.Objective: The objective was to identify, critically examine, and summarize studies investigating the short-term response of gastrointestinal hormones to food in persons with an ED, including the subtypes anorexia nervosa and bulimia nervosa.Design: A priori inclusion and exclusion criteria were set and included a procedure in which a test meal or glucose load was given and blood hormone concentrations measured. All studies included a healthy control group for comparison. The outcome variable was defined as the mean difference between fasting plasma hormone concentrations and the maximum postprandial peak or nadir. The difference in baseline values between groups was also examined. Pooled standardized mean differences were calculated and analyzed where possible.Results: A total of 28 studies were identified, including sufficient studies to perform a meta-analysis for ghrelin, peptide YY, cholecystokinin, insulin, and pancreatic polypeptide. Persons with an ED had higher baseline concentrations of ghrelin (large effect), peptide YY (medium effect), and cholecystokinin (medium effect for ED, large effect for anorexia nervosa). The response of insulin to food was decreased in persons with an ED (medium effect). No further differences were found in the release of gut peptides to a standardized test meal.Conclusions: All of the studies had low power for the different subtypes of EDs. High heterogeneity among the studies was observed, and limitations are discussed. The findings suggest that the physiologic changes observed in patients with EDs are highly variable and subject to multiple confounding factors.

Effects of Adenine on the Pituitary-Gonad Axis in Newborns Rats

The present study was undertaken to investigate effects of the adenine on the hypothalamus-pituitary-gonad axis and changes in blood hormone concentration such as FSH, LH, progesterone and estrogen in newborn female rats. Adenine is a common organic base and its concentration variations caused by foods, has various effects on the body metabolic systems. In present study, fifty newborns rats were used divided into five groups, of 10s, including control I, control II which received solvent (normal saline) only and three experimental groups which received 50, 100 and 200 mg body weight adenine respectively. All the animals were kept under same condition with plenty food and water and treated Intra Peritoneally (IP) during days 2-16 after birth. At the end of experiment, all the animals were weighed, their ovaries were removed and blood samples were taken for hormone analysis. The results showed that dose dependent adenine solution significantly reduced the body and ovarian weight on 30 and 70 days after birth. In addition adenine led into no significant difference in concentration of FSH and LH in the experimental groups relative to the control on 30th day of life. But on the 70th day, the levels of these hormones raised significantly in the experimental groups. Furthermore, the adenine solution significantly increased the levels of progesterone and estrogen hormones in the experimental groups relative to the control on the 30th day, while decreased their concentration significantly on the 70th day. This situation has close similarities to metabolic disorders present in human caused by excessive use of adenine. High amounts consumption of adenine in can lead into hormone abnormality, weight loss and metabolic anomalies.

Cross-Transfer Effects of Resistance Training with Blood Flow Restriction

This study investigated whether muscle hypertrophy-promoting effects are cross-transferred in resistance training with blood flow restriction, which has been shown to evoke strong endocrine activation. Fifteen untrained men were randomly assigned into the occlusive training group (OCC, N = 8) and the normal training group (NOR, N = 7). Both groups performed the same unilateral arm exercise (arm curl) at 50% of one-repetition maximum (1RM) without occlusion (three sets, 10 repetitions). Either the dominant or nondominant arm was randomly chosen to be trained (OCC-T, NOR-T) or to serve as a control (OCC-C, NOR-C). After the arm exercise, OCC performed leg exercise with blood flow restriction (30% of 1RM, three sets, 15-30 repetitions), whereas NOR performed the same leg exercise without occlusion. The training session was performed twice a week for 10 wk. In a separate set of experiments, acute changes in blood hormone concentrations were measured after the same leg exercises with (N = 5) and without (N = 5) occlusion. Cross-sectional area (CSA) and isometric torque of elbow flexor muscles increased significantly in OCC-T, whereas no significant changes were observed in OCC-C, NOR-T, and NOR-C. CSA and isometric torque of thigh muscles increased significantly in OCC, whereas no significant changes were observed in NOR. Noradrenaline concentration showed a significantly larger increase after leg exercise with occlusion than after exercises without occlusion, though growth hormone and testosterone concentrations did not show significant differences between these two types of exercises. The results indicate that low-intensity resistance training increases muscular size and strength when combined with resistance exercise with blood flow restriction for other muscle groups. It was suggested that any circulating factor(s) was involved in this remote effect of exercise on muscular size.

Effect of Hoof Trimming before the Dry Period on Productive Performance in Perinatal Dairy Cows

To investigate the effect of hoof trimming before the dry period, the hooves of 10 cows (trimmed group) were trimmed at 79.6 +/- 8.6 days before parturition and the hooves of 52 cows were left untrimmed (control group). Blood biochemistry and hormone concentrations were investigated for 6 cows from each group. The daily milk yield after parturition in the trimmed group tended to be higher than that of the control group. Between 0 and 30 days after parturition, the levels of non-esterified fatty acids were significantly lower stet, and the plasma glucose and glucose disposal rates were significantly higher in the trimmed group. The plasma cortisol concentration was stable before and after parturition in the trimmed group. Hoof trimming before the dry period appears to reduce stress and maintain the nutritional conditions of perinatal dairy cows.

Effect of dietary enrichment with either n-3 or n-6 fatty acids on systemic metabolite and hormone concentration and ovarian function in heifers

The objective of this experiment was to examine the effects of dietary n-3 or n-6 fatty acid (FA) supplementation on blood FA, metabolite and hormone concentrations, follicle size and dynamics and corpus luteum (CL) size. Reproductively normal heifers (n = 24) were individually fed diets of chopped straw and concentrate containing either (i) no added lipid (CON; n = 8); (ii) 2% added fat as whole raw soya beans (WSB, n-6; n = 8); or (iii) 2% added fat as fish oil (FO, n-3; n = 8). Following oestrous cycle synchronisation, blood samples were collected at appropriate times and intervals for the measurement of hormones, FAs and metabolites. On days 15 and 16 of the cycle, animals were subjected to an intravenous oxytocin challenge and prostaglandin F2α (PGF2α) response, measured as venous concentrations of 13,14-dihydro-15-keto PGF2α (PGFM). Dry matter intake and average daily gain were similar among treatments (P > 0.05). Plasma concentration of linoleic acid was highest on WSB (P < 0.05), while eicosapentaenoic (EPA, n-3; P < 0.0001) and docosahexaenoic acid (DHA, n-3; P < 0.0001) were greatest in the FO group. Plasma concentrations of arachidonic acid were higher on FO (P < 0.05) compared with CON and WSB. Plasma triglyceride concentrations increased, while β-hydroxybutyrate (BHBA) decreased with time on all diets (P < 0.05). There was a diet × time interaction (P < 0.01) for non-esterified fatty acid (NEFA) concentrations. Plasma cholesterol was higher on WSB and FO (P < 0.01) compared with CON. Progesterone (P4) and oestradiol (E2) concentrations, as well as follicle growth rate and CL diameter were similar across diets (P > 0.05). There was a diet × day interaction for PGFM (P < 0.01). When corrected for systemic E2 : P4 ratio, day 15 concentrations of PGFM were higher in the WSB group at 15 and 30 min (P < 0.01) post oxytocin administration compared with CON and FO, which were similar (P > 0.05). Concentrations of PGFM on day 16 were similar for WSB and FO and were greater than CON at 15 (P < 0.01) and 45 min (P < 0.05) post oxytocin administration, and at 30 min for FO (P < 0.05). With the exception of PGFM, dietary lipid source did not affect the reproductive variables measured.

Novel trends in endocrine disruptor testing: the H295R Steroidogenesis Assay for identification of inducers and inhibitors of hormone production

IntroductionOver the past two decades, there has been increasingconcern about the possible impacts of exposure to chem-icals in the environment on endocrine and reproductivesystems in humans and wildlife [1]. To address theseconcerns, national and international programs have beeninitiated to develop new guidelines for the screening andtesting of potential endocrine-disrupting chemicals (EDCs)in vertebrates [2, 3]. The focus of these multi-tieredprograms was to develop in vitro and in vivo assays toidentify and classify chemicals relative to their potentialinteraction with endocrine systems (Tier 1), and then todevelop concentration–response relationships in animalmodels (Tier 2) [2]. In this article we will focus on a newin vitro bioassay to test for the potential of chemicals tointerfere with steroid hormone production. This assay iscurrently being developed as part of Tier 1 of the USEPAEndocrine Disruptor Screening Program and an Organiza-tion for Economic Cooperation and Development (OECD)test method validation program [4].Most of the efforts to develop screening assays forendocrine disruptor testing have been focused on thedevelopment and validation of in vitro hormone receptor-binding assays including the estrogen receptor (ER) and theandrogen receptor (AR) [5–7]. However, it should beacknowledged that there are a number of non-receptor-mediated processes that may also alter endocrine function[8]. These include chemical-induced modulation of theenzymes involved in the production, transformation, orelimination of steroid hormones, which can result inalterations of the absolute and relative concentrations ofhormones in blood and tissues [9]. Often, these non-receptor-mediated effects are caused indirectly via alter-ations of common signal-transduction pathways [10], orthrough direct competitive or non-competitive inhibition ofthe enzyme.Steroid sex hormones are key factors involved in theregulation of reproduction in vertebrates and are alsoinvolved in numerous other processes that are related todevelopment and growth [11]. Thus, chemicals that candisrupt the production of sex steroids may be directlylinked to adverse outcomes for these processes. To addressthe potential issues of exposure to chemicals that may resultin the disturbance of sex steroid homeostasis, therefore,several in vivo test systems have been evaluated. Thesetests include the pubertal male and female rat assays, thefish reproductive screen, and the frog thyroid assay.Furthermore, several in vitro screening methods have beendeveloped including the microsomal aromatase assay and arodent minced-testis assay [2]. Some of these assays suchas the rodent minced-testis have shown some promiseregarding their potential to identify effects on androgenproduction. However, a number of questions have beenraised about the utility of rodent–based explant assays inthat they were found to yield high rates of false positive or

Measurement of Porcine Luteinizing Hormone Concentration in Blood by Time-Resolved Fluoroimmunoassay

We validated a time-resolved fluoroimmunoassay (TR-FIA) using the lanthanide element europium as a non-radiological tracer for measuring luteinizing hormone (LH) in porcine peripheral blood. The dose-response curve of the reference standard ranged from 0.2048 to 50 ng/ml. Good parallelism was noted between the LH standard and plasma sample. The profile of LH throughout the estrous cycle, assessed by daily blood sampling, was consistent with the previous findings obtained by radioimmunoassays (RIAs). Moreover, the secretory patterns of pulsatile LH in the follicular phase and the preovulatory LH surge were also similar to those obtained in previous RIAs. We conclude that TR-FIA can be used to measure LH levels in porcine blood, with practical and convenient applications.

Upconversion Fluorescence Enables Homogeneous Immunoassay in Whole Blood

Many medical conditions are related to alterations in protein or hormone concentrations in blood. These changes are commonly detected with heterogeneous immunoassays that require a separation step before signal measurement. A simple homogeneous assay performable directly in whole blood would be useful in clinical diagnostics, but the performance of homogeneous fluorescence-based immunoassays has been severely limited by autofluorescence and strong absorption of ultraviolet and visible light in whole blood. These problems might be avoided by the use of near-infrared excited upconversion fluorescence. We recently described a novel homogeneous assay method based on upconversion fluorescence resonance energy transfer (FRET). In this method an upconverting phosphor (UCP) is used as a donor and a fluorescent protein or a small-molecular fluorescent dye is used as an acceptor (1)(2). We report here the use of a competitive homogeneous immunoassay for 17β-estradiol (E2) in whole blood as a model to demonstrate the application of upconversion FRET using a near-infrared fluorescent acceptor dye (Fig. 1A⇓ ; and see Fig. 1 in the Data Supplement that accompanies the online version of this Letter at http://www.clinchem.org/content/vol53/issue1). Figure 1. Principle ( A ) and standard curves ( B ) of the upconversion FRET-based competitive homogeneous E2 immunoassay. ( A ), the anti-E2-Fab-coated FCD-546–1 UCP (donor) can bind E2 (analyte) and E2-AF680 conjugate (acceptor). Phosphor emission at …

Thyroid hormones in small ruminants: effects of endogenous, environmental and nutritional factors

Appropriate thyroid gland function and thyroid hormone activity are considered crucial to sustain the productive performance in domestic animals (growth, milk or hair fibre production). Changes of blood thyroid hormone concentrations are an indirect measure of the changes in thyroid gland activity and circulating thyroid hormones can be considered as indicators of the metabolic and nutritional status of the animals. Thyroid hormones play a pivotal role in the mechanisms permitting the animals to live and breed in the surrounding environment. Variations in hormone bioactivity allow the animals to adapt their metabolic balance to different environmental conditions, changes in nutrient requirements and availability, and to homeorhetic changes during different physiological stages. This is particularly important in the free-ranging and grazing animals, such as traditionally reared small ruminants, whose main physiological functions (feed intake, reproduction, hair growth) are markedly seasonal. Many investigations dealt with the involvement of thyroid hormones in the expression of endogenous seasonal rhythms, such as reproduction and hair growth cycles in fibre-producing (wool, mohair, cashmere) sheep and goats. Important knowledge about the pattern of thyroid hormone metabolism and their role in ontogenetic development has been obtained from studies in the ovine foetus and in the newborn. Many endogenous (breed, age, gender, physiological state) and environmental factors (climate, season, with a primary role of nutrition) are able to affect thyroid activity and hormone concentrations in blood, acting at the level of hypothalamus, pituitary and/or thyroid gland, as well as on peripheral monodeiodination. Knowledge on such topics mirror physiological changes and possibly allows the monitoring and manipulation of thyroid physiology, in order to improve animal health, welfare and production.

Postprandial blood hormone and metabolite concentrations influenced by feeding frequency and feeding level in veal calves

This study hypothesized that increased feeding frequency (FF) decreases problems with glucose homeostasis seen at high feeding levels (FL) in heavy veal calves. Effects of FF and FL on hormone and metabolite concentrations were studied in 15 heavy veal calves fed once (FF1; at 12:00), twice (FF2; at 12:00 and 24:00) or four times daily (FF4; at 06:00, 12:00, 18:00 and 24:00). In period 1, all calves were fed at a low FL (FL low; 1.5 × metabolizable energy requirements for maintenance, ME m). In period 2, FF2 and FF4 calves were fed at high FL (FL high; 2.5 × ME m), whereas FF1 calves were still fed at FL low. Blood was sampled every 30 min from 12:00 to 18:00 and postprandial integrated plasma hormone and metabolite concentrations (AUC 12–18 h ) were calculated. Glucose AUC 12–18 h increased with increasing FL, but decreased with increasing FF, urea AUC 12–18 h increased with increasing FL, whereas non-esterified fatty acid AUC 12–18 h were unaffected by FL and FF. Insulin AUC 12–18 h decreased with increasing FF and decreasing FL. Glucagon AUC 12–18 h increased with increasing FL and FF. Growth hormone AUC 12–18 h decreased, whereas insulin-like growth factor-1 and leptin AUC 12–18 h increased with increasing FL. Mean thyroxine and 3,5,3′-triiodothyronine concentrations were modified by FF and FL. There were no FF × FL interactions, except for plasma glucose. In conclusion, postprandial hormone and metabolite responses were differentially affected by FF and (or) FL. Glucose and insulin concentrations were maximally increased at high FL and low FF. Hyperglycemia, glucosuria and excessive insulinemia were prevented by increasing FF and decreasing FL.

Oxytocin levels in the posterior pituitary and in the heart are modified by voluntary wheel running

We hypothesized that voluntary wheel running results in increased secretion of oxytocin, a peptide involved in the stress response. An additional hypothesis was that prolonged exercise affects oxytocin levels in the heart, which is in line with the potential role of oxytocin in cardiovascular functions. Voluntary wheel running lasted 3 weeks and daily running distances increased progressively reaching maximum levels about 8 km (Sprague–Dawley rats) and 4 km (Lewis strain). The exercise resulted in significant reduction of epididymal fat, slight increase in glucose transporter GLUT4 mRNA levels and significant enhancement of plasma density. Voluntary exercise failed to influence plasma oxytocin levels either in Lewis or Sprague–Dawley rats, but it resulted in a significant decrease of oxytocin concentrations in the posterior pituitary. Plasma oxytocin concentrations were not modified even if the measurements were made in the dark phase of the day. In voluntary wheel running Sprague–Dawley rats, the content of oxytocin in the right heart atrium was lower than in controls. Thus, the present findings demonstrate that prolonged voluntary wheel running results in a decrease in pituitary oxytocin content without evident changes in hormone concentrations in peripheral blood. However, prolonged exercise used has a significant impact on oxytocin levels in the heart.

Correlation between serum and fecal concentrations of reproductive steroids throughout gestation in goats

Non-invasive techniques such as the measurement of fecal steroids are now widely used to monitor reproductive hormones in captive and free-ranging wild-life. These methods offer great advantages and deserve to be used in domestic animals. The aim of the present study was to determine the endocrine profile of dairy goats throughout pregnancy by the quantification of fecal progestins and estrogens and assess its correlation with serum concentrations. Blood and fecal samples were collected weekly from 11 adult, multiparous goats, from mating through pregnancy and 2 weeks post-partum. The extraction of estradiol and progesterone fecal metabolites was performed by dilution in ethanol. The radioimmunoassay (RIA) in solid phase was used to quantify serum 17β-estradiol (estradiol) and progesterone, as well as their fecal metabolites. The mean concentrations of both fecal and serum estradiol started to increase between weeks 7 and 11, reached peak values near parturition and then decreased sharply (range: 19.8 ± 5.8 ng/g of feces to 608.6 ± 472.4 ng/g of feces and 0.007 ± 0.005 ng/ml to 0.066 ± 0.024 ng/ml). An increase in both fecal and blood progestagens occurred in the second week, mean concentrations remained greater until week 20, and then decreased in the last week of gestation and 2 weeks post-partum (range: 108.8 ± 43.6 ng/g of feces to 3119.5 ± 2076.9 ng/g of feces and 0.12 ± 0.04 ng/ml to 13.10 ± 4.29 ng/ml). The changes in blood and fecal hormone concentrations were analyzed and compared throughout gestation for each single goat, for each breed and for the whole group. Results indicated that matched values of serum and fecal hormone concentrations were correlated ( r = 0.79; p < 0.001 for progesterone and r = 0.84; p < 0.001 for estradiol mean concentrations in the whole group). Regression analysis showed that logarithmic model allows significant prediction of serum from fecal concentrations with an R 2 = 0.729 ( y = 0.013 ln x − 0.021) for estradiol and R 2 = 0.788 ( y = 3.835 ln x − 18.543) for progesterone. Neither fecal nor serum concentrations were affected by the breed but a significant effect of the number of fetuses on progestin concentrations was found. Therefore, the profiles of progesterone and estradiol fecal metabolites reflect the serum concentrations of the same hormones in pregnant goats.

Relationship of alcohol intake and sex steroid concentrations in blood in pre- and post-menopausal women: the European Prospective Investigation into Cancer and Nutrition

Women with a moderate intake of alcohol have higher concentrations of sex steroids in serum, and higher risk of developing breast cancer, compared to non-drinkers. In the present study, we investigate the relationships between alcohol consumption and serum levels of sex steroids and sex-hormone binding globulin (SHBG) in 790 pre- and 1,291 post-menopausal women, who were part of the European Prospective Investigation into Cancer and Nutrition (EPIC). Serum levels of testosterone (T), androstenedione (Delta4), dehydroepiandrosterone sulphate (DHEAS), estrone (E1), estradiol (E2) and SHBG were measured by direct immunoassays. Free T (fT) and free E2 (fE2) were calculated according to mass action laws. Current alcohol intake exposure to alcohol was assessed from dietary questionnaires. Pre-menopausal women who consumed more than 25 g/day of alcohol had about 30% higher DHEAS, T and fT, 20% higher Delta4 and about 40% higher E1, concentrations compared to women who were non-consumers. E2, fE2 and SHBG concentrations showed no association with current alcohol intake. In post-menopausal women, DHEAS, fT, T, Delta4, and E1 concentrations were between 10% and 20% higher in women who consumed more than 25 g/day of alcohol compared to non-consumers. E2 or fE2 were not associated with alcohol intake at all. SHBG levels were about 15% lower in alcohol consumers compared to non-consumers. This study supports the hypothesis of an influence of alcohol intake on sex hormone concentrations in blood.

Effect of the copper-intrauterine device (TCu 380A) on subendometrial microvascularization and uterine artery blood flow

During this cohort study, the copper-intrauterine device (IUD) did not modify subendometrial microvascularization. However, subendometrial blood flow increased in patients who experienced IUD-induced side effects.

수영거리가 근대5종 선수들의 호르몬 농도에 미치는 영향

수영거리가 근대5종 선수들의 호르몬 농도에 미치는 영향

Physical characteristics, blood hormone concentrations, and plasma lipid concentrations in obese horses with insulin resistance

To compare obese horses with insulin resistance (IR) with nonobese horses and determine whether blood resting glucose, insulin, leptin, and lipid concentrations differed between groups and were correlated with combined glucose-insulin test (CGIT) results. 7 obese adult horses with IR (OB-IR group) and 5 nonobese mares. Physical measurements were taken, and blood samples were collected after horses had acclimated to the hospital for 3 days. Response to insulin was assessed by use of the CGIT, and maintenance of plasma glucose concentrations greater than the preinjection value for > or = 45 minutes was used to define IR. Area under the curve values for glucose (AUC(g)) and insulin (AUC(i)) concentrations were calculated. Morgan, Paso Fino, Quarter Horse, and Tennessee Walking Horse breeds were represented in the OB-IR group. Mean neck circumference and BCS differed significantly between groups and were positively correlated with AUC values. Resting insulin and leptin concentrations were 6 and 14 times as high, respectively, in the OB-IR group, compared with the nonobese group, and were significantly correlated with AUC(g) and AUC(i). Plasma nonesterified fatty acid, very low-density lipoprotein, and high-density lipoprotein-cholesterol (HDL-C) concentrations were significantly higher (86%, 104%, and 29%, respectively) in OB-IR horses, and HDL-C concentrations were positively correlated with AUC values. Measurements of neck circumference and resting insulin and leptin concentrations can be used to screen obese horses for IR. Dyslipidemia is associated with IR in obese horses.

Effects of body condition score at parturition and postpartum supplemental fat on metabolite and hormone concentrations of beef cows and their suckling calves1

To determine the effects of BCS at parturition and postpartum lipid supplementation on blood metabolite and hormone concentrations, 3-yr-old Angus x Gelbvieh beef cows, which were nutritionally managed to achieve a BCS of 4 +/- 0.07 (479.3 +/- 36.3 kg of BW) or 6 +/- 0.07 (579.6 +/- 53.1 kg of BW) at parturition, were used in a 2-yr experiment (n = 36/yr). Beginning at 3 d postpartum, cows within each BCS were assigned randomly to be fed hay and a low-fat control supplement or lipid supplements with either cracked high-linoleate or high-oleate safflower seeds until d 61 of lactation. The diets were formulated to be isonitrogenous and isocaloric, and the safflower seed supplements were formulated to achieve 5% DMI as fat. On d 31 and 61 of lactation, blood samples were collected preprandially and then hourly postprandially (at 0, 1, 2, 3, and 4 h). Serum insulin (P = 0.27) and glucose (P = 0.64) were not affected by BCS at parturition. The mean concentrations of plasma NEFA (P = 0.08) and beta-hydroxybutyrate (P = 0.08) tended to be greater, and serum IGF-I was greater (P < 0.001) in BCS 6 than BCS 4 cows. Conversely, serum GH was greater (P = 0.003) for BCS 4 cows, indicating that regulation of IGF by GH may have been uncoupled in BCS 4 cows. The postpartum diet did not affect NEFA (P = 0.94), glucose (P = 0.15), IGF-I (P = 0.33), or GH (P = 0.62) concentrations. Oleate-supplemented cows had greater (P = 0.03) serum insulin concentrations, whereas control cows had greater (P = 0.01) plasma beta-hydroxybutyrate concentrations. Concentrations of NEFA (P = 0.05) and glucose (P < 0.001) were greater, and beta-hydroxybutyrate tended (P = 0.07), to be greater at d 3, whereas serum IGF-I was greater (P = 0.003) at d 6 of lactation. Similar concentrations of NEFA, glucose, GH, and IGF-I indicate that the nutritional status of beef cows during early lactation was not influenced by lipid supplementation. However, perturbations of the somatotropic axis in BCS 4 cows indicate that the influence of energy balance and BCS of the cow at parturition on postpartum performance should be considered when making managerial decisions.

Postprandial Suppression of Glucagon Secretion Depends on Intact Pulsatile Insulin Secretion

Type 2 diabetes is characterized by an approximately 60% loss of beta-cell mass, a marked defect in postprandial insulin secretion, and a failure to suppress postprandial glucagon concentrations. It is possible that postprandial hyperglucagonemia in type 2 diabetes is due to impaired postprandial insulin secretion. To address this, we studied eight adult Goettingen minipigs before and after an approximately 60% reduction in beta-cell mass induced by alloxan. Pigs were studied fasting and after ingestion of a mixed meal. Insulin and glucagon secretion were determined by deconvolution of blood hormone concentrations measured at 1-min intervals. The relationship between insulin and glucagon release was analyzed using cross-correlation and forward versus reverse cross-approximate entropy. We report that glucagon and insulin were secreted in approximately 4-min pulses. Prealloxan, postprandial insulin secretion drove an approximately 20% suppression of glucagon concentrations (P < 0.01), through inhibition of glucagon pulse mass. The alloxan-induced approximately 60% deficit in beta-cell mass lead to an approximately 70% deficit in postprandial insulin secretion and loss of the postprandial insulin-driven suppression of glucagon secretion. We conclude that postprandial hyperglucagonemia in type 2 diabetes is likely due to loss of intraislet postprandial suppression of glucagon secretion by insulin.

Endocrine responses to acute and chronic high-altitude exposure (4,300 meters): modulating effects of caloric restriction

High-altitude anorexia leads to a hormonal response pattern modulated by both hypoxia and caloric restriction (CR). The purpose of this study was to compare altitude-induced neuroendocrine changes with or without energy imbalance and to explore how energy sufficiency alters the endocrine acclimatization process. Twenty-six normal-weight, young men were studied for 3 wk. One group [hypocaloric group (HYPO), n = 9] stayed at sea level and consumed 40% fewer calories than required to maintain body weight. Two other groups were deployed to 4,300 meters (Pikes Peak, CO), where one group (ADQ, n = 7) was adequately fed to maintain body weight and the other [deficient group (DEF), n = 10] had calories restricted as above. HYPO experienced a typical CR-induced reduction in many hormones such as insulin, testosterone, and leptin. At altitude, fasting glucose, insulin, and epinephrine exhibited a muted rise in DEF compared with ADQ. Free thyroxine, thyroid-stimulating hormone, and norepinephrine showed similar patterns between the two altitude groups. Morning cortisol initially rose higher in DEF than ADQ at 4,300 meters, but the difference disappeared by day 5. Testosterone increased in both altitude groups acutely but declined over time in DEF only. Adiponectin and leptin did not change significantly from sea level baseline values in either altitude group regardless of energy intake. These data suggest that hypoxia tends to increase blood hormone concentrations, but anorexia suppresses elements of the endocrine response. Such suppression results in the preservation of energy stores but may sacrifice the facilitation of oxygen delivery and the use of oxygen-efficient fuels.

MPA 투여가 사슴뿔의 성장에 미치는 영향

S.W.Kim*,S.H.Choi*,B.D.Sang*,Y.K.Kim*,C.H.Yoo*andK.W.Seo**NationalLivestockResearchInstitute,R.D.A.*,DepartmentofDairyScience,ChungNamNationalUniversity**ABSTRACTThe study was conducted to determine the effects of hormone injection on casting day of antler, velvetantler yield, and blood hormone concentration in elk deer and Sika deer. The study revealed that thecasting day of Elk and Sika deer at medroxy progesterone acetate(MPA) injection averaged 21 days afterMPA injection, which was earlier 38 and 24 days, respectively, compared control(P<0.01). The regrowthof antler in bothSika deerandElkoccurredintheMPA injectionand theduration ofantlergrowthwas2times longerthancontrol. The totalyield of velvetantlerofElk inthe control andMPA injection was7.31 and 10.11kg and the that of sika deer was 1.00 and 1.41kg, respectively. Blood testosteroneconcentration of Sika deer and Elk was less than 4.0ng/ml for both at the casting and during the antlergrowing. Blood IGF-1 concentrations of Sika deer and Elk during the antler growing tended to increasewiththesameasgrowthcurveofantler.(Keywords :Velvetantler,casting,MPA,Hormone,Yield)