Key Specifications Table
|Analytes Available||Species Reactivity||Key Applications||Detection Methods|
|Description||Human Ghrelin (ACTIVE) RIA|
|Background Information||Ghrelin is a recently discovered hormone is secreted primarily by the stomach in response to glucose administration or CNS signals.|
|Detection method||Radioactive 125I|
|Linearity of Dilution||100–142.5%|
|Standard Curve Range||
|Safety Information according to GHS|
|Storage and Shipping Information|
|Material Size||125 tubes|
|Protocol: Ghrelin (Active) Radioimmunoassay (RIA) Kit|
Human Ghrelin (ACTIVE) RIA SDS
|Reference overview||Pub Med ID|
|Total and acylated ghrelin levels in children with poor growth.|
Jordan E Pinsker,Deborah Ondrasik,Debora Chan,Gregory J Fredericks,Eludrizza Tabisola-Nuesca,Minela Fernandez-Aponte,Dean R Focht,Merrily Poth
Pediatric research 69 2011
Ghrelin, an enteric hormone with potent appetite stimulating effects, also stimulates growth hormone release. We hypothesized that altered levels of total ghrelin (TG) or acylated ghrelin (AG) could affect growth by altering growth hormone secretion, subsequently affecting insulin-like growth factor-1 (IGF-1) generation or by altering appetite and food intake. After institutional review board approval, 52 children presenting for evaluation of chronic gastrointestinal symptoms (group 1), poor weight gain (group 2), or poor linear growth (group 3) were evaluated for fasting TG and AG levels in addition to their regular evaluation. Serum ghrelin, IGF-1, and prealbumin were compared between groups. No difference was observed for mean fasting TG between groups. However, mean fasting AG was highest in patients in group 2 (465 ± 128 pg/mL) versus group 1 (176 ± 37 pg/mL) and group 3 (190 ± 34 pg/mL). IGF-1 was lowest in patients in group 2 despite similar prealbumin levels among the three groups. We conclude that serum AG levels are highest in children with isolated poor weight gain compared with children with short stature or chronic gastrointestinal symptoms, suggesting the possibility of resistance to AG in underweight children. Additional studies are needed to further clarify ghrelin's role in growth and appetite.
|Acute differential effects of milk-derived dietary proteins on postprandial lipaemia in obese non-diabetic subjects.|
Holmer-Jensen J, Hartvigsen ML, Mortensen LS, Astrup A, de Vrese M, Holst JJ, Thomsen C, Hermansen K
European journal of clinical nutrition 2011
Background/Objectives:Postprandial lipaemia is an established risk factor for atherosclerosis. To investigate the acute effect of four milk-derived dietary proteins (alpha-lactalbumin, whey isolate, caseinoglycomacropeptide and whey hydrolysate) on postprandial lipaemia, we have conducted a randomized, acute, single-blinded clinical intervention study with crossover design.Subjects/Methods:A total of 11 obese non-diabetic subjects (age: 44-74, BMI: 30-41.4 kg m(-2)) were included. On 4 different days the subjects ingested a high-fat meal with the following energy distribution: 66% energy from fat (100 g of butter), 15% of energy from carbohydrate (90 g of white wheat bread) and 19% of energy from protein (45 g of pure protein). Our primary variable was plasma triglyceride measured in the 8-h postprandial period. Secondarily, retinyl palmitate, non-esterified free fatty acids, glucose, insulin, glucagon, GLP-1 and GIP, active and total grehlin and cholecystokinin were measured.Results:We observed no statistically significant (P=0.8) differences between meals on our primary variable that is, triglycerides. Whey hydrolysate was associated with a significantly (P=0.02) smaller postprandial suppression of non-esterified free fatty acids compared with the other dietary proteins.Conclusion:We did not observe significant differences in postprandial lipaemia to the four milk-derived dietary proteins. Whey hydrolysate caused less postprandial suppression of free fatty acids.European Journal of Clinical Nutrition advance online publication, 27 July 2011; doi:10.1038/ejcn.2011.142.
|Metabolic state alters economic decision making under risk in humans.|
Symmonds, Mkael, et al.
PLoS ONE, 5: e11090 (2010) 2010
Animals' attitudes to risk are profoundly influenced by metabolic state (hunger and baseline energy stores). Specifically, animals often express a preference for risky (more variable) food sources when below a metabolic reference point (hungry), and safe (less variable) food sources when sated. Circulating hormones report the status of energy reserves and acute nutrient intake to widespread targets in the central nervous system that regulate feeding behaviour, including brain regions strongly implicated in risk and reward based decision-making in humans. Despite this, physiological influences per se have not been considered previously to influence economic decisions in humans. We hypothesised that baseline metabolic reserves and alterations in metabolic state would systematically modulate decision-making and financial risk-taking in humans.
|Comparison of Competitive Radioimmunoassays and Two-Site Sandwich Assays for the Measurement and Interpretation of Plasma Ghrelin Levels.|
Prudom C, Liu J, Patrie J, Gaylinn BD, Foster-Schubert KE, Cummings DE, Thorner MO, Geysen HM
The Journal of clinical endocrinology and metabolism 2010
Context: Ghrelin, an endogenous ligand for the GH secretagogue receptor, is an orexigenic peptide hormone produced primarily by the stomach. Recent studies suggest significant differences in the specificity of currently available ghrelin assays. Objective: The aim of the study was to compare four ghrelin assays (two commercially available and two developed by our group) of differing specificity, each used on the same set of more than 800 plasma samples from a human study. Design: Thirteen volunteers were sampled every 20 min for 6 h after consumption of one of three isocaloric drinks consisting of either 80% fat, 80% carbohydrate, or 80% protein. The samples were assayed by RIA for total and active ghrelin, as well as by sandwich assays for acyl and des-acyl ghrelin. The ghrelin profiles for each individual were smoothed using a statistical algorithm to lessen the effects of pulsatility and noise. Results: The sandwich assays for acyl and des-acyl ghrelin yielded ghrelin values that were lower than those from the corresponding RIAs. The ghrelin profiles after nutrient ingestion were similar, yet key differences among the four assays were apparent; in particular, percentage changes were significantly greater in the sandwich assays. Conclusions: The lower levels and greater relative changes in ghrelin values reported by the sandwich assays are consistent with greater assay specificity. When applied to the nutrient study, the sandwich assays were better able to distinguish the different responses to different nutrients than were the RIAs.
|Effect of feed restriction and supplemental dietary fat on gut peptide and hypothalamic neuropeptide messenger ribonucleic acid concentrations in growing wethers.|
Relling AE, Pate JL, Reynolds CK, Loerch SC
Journal of animal science 88 737-48 2009
The objectives of the present study were 1) to evaluate the effects of supplemental fat and ME intake on plasma concentrations of glucagon-like peptide-1 (GLP-1), cholecystokinin (CCK), glucose-dependent insulinotropic polypeptide, ghrelin, and oxyntomodulin; and 2) to determine the association of these peptides with DMI and the hypothalamic concentration of mRNA for the following neuropeptides: neuropeptide Y (NPY), agouti-related peptide (AgRP), and proopiomelanocortin (POMC). In a completely randomized block design with a 2 x 2 factorial arrangement of treatments, 32 pens with 2 wethers each were restricted-fed (2.45 Mcal/lamb per day) or offered diets ad libitum (n = 16) with or without 6% supplemental fat (n = 16) for a period of 30 d. Dry matter intake was measured daily. On d 8, 15, 22, and 29, BW was measured before feeding, and 6 h after feeding, blood samples were collected for plasma measurement of insulin, GLP-1, CCK, ghrelin, glucose-dependent insulinotropic polypeptide, oxyntomodulin, glucose, and NEFA concentrations. On d 29, blood was collected 30 min before feeding for the same hormone and metabolite analyses. At the end of the experiment, wethers were slaughtered and the hypothalami were collected to measure concentrations of NPY, AgRP, and POMC mRNA. Offering feed ad libitum (resulting in greater ME intake) increased plasma insulin and NEFA concentrations (P = 0.02 and 0.02, respectively) and decreased hypothalamic mRNA expression of NPY and AgRP (P = 0.07 and 0.02, respectively) compared with the restricted-fed wethers. There was a trend for the addition of dietary fat to decrease DMI (P = 0.12). Addition of dietary fat decreased insulin and glucose concentrations (P 0.05 and 0.01, respectively) and tended to increase hypothalamic mRNA concentrations for NPY and AgRP (P = 0.07 and 0.11, respectively). Plasma GLP-1 and CCK concentrations increased in wethers offered feed ad libitum compared with restricted-fed wethers, but the response was greater when wethers were offered feed ad libitum and had supplemental fat in the diet (fat x intake interaction, P = 0.04). The prefeeding plasma ghrelin concentration was greater in restricted-fed wethers compared with those offered feed ad libitum, but the concentrations were similar 6 h after feeding (intake x time interaction, P 0.01). Supplemental dietary fat did not affect (P = 0.22) plasma ghrelin concentration. We conclude that insulin, ghrelin, CCK, and GLP-1-05-regulate DMI in sheep by regulating the hypothalamic gene expression of NPY, AgRP, and POMC.
|Ghrelin, paraoxonase and arylesterase levels in depressive patients before and after citalopram treatment.|
Abdullah Onder Barim, Suleyman Aydin, Ramis Colak, Ersel Dag, Omer Deniz, Ibrahim Sahin
Clinical biochemistry 42 1076-81 2009
OBJECTIVES: The purpose of this study was to examine alterations in lipid profiles and in the serum concentrations of acylated and desacylated ghrelin, paraoxonase and arylesterase in psychiatric patients before and after treatment with 40 mg citalopram daily for 3 months. DESIGN AND METHODS: Samples were collected from 22 healthy controls and 24 psychiatric patients before and after citalopram treatment. Blood levels of acylated and desacylated ghrelin were measured by radioimmunoassay. Paraoxonase and arylesterase activities were determined spectrophotometrically. Lipid parameters were measured on the OLYMPUS-AU400. RESULTS: It was found that the levels of acylated, desacylated ghrelin, paraoxonase arylesterase, total cholesterol and triglyceride were lower in depressive patients before citalopram treatment than in the control group. Those parameters were not restored after citalopram treatment except for the arylesterase level. CONCLUSION: Decreased PON1 and ghrelin levels as well as fluctuations in lipid profiles may be involved in the etiology of depressive disorders.
|Restricting time at pasture: effects on dairy cow herbage intake, foraging behavior, hunger-related hormones, and metabolite concentration during the first grazing session.|
Gregorini P, Clark CE, Jago JG, Glassey CB, McLeod KL, Romera AJ
Journal of dairy science 92 4572-4580 2009
This study investigated the effect of restricting grazing time on circulating concentrations of ghrelin, nonesterified fatty acids (NEFA), and glucose before, and foraging behavior of dairy cows during, the first grazing session of the day (GS, 0800-1200 h). Forty-eight Holstein-Friesian cows (470 +/- 47 kg of BW; 35 +/- 9 d in milk) were strip-grazed on a perennial ryegrass pasture for either 4 h after each milking (2 x 4), 8 h between milkings (1 x 8), or the 24-h period excluding milking times (CTL). Cows were bled before the GS; plasma was analyzed for ghrelin and serum for glucose and NEFA. Herbage mass was measured pregrazing (0730 h), during and at the end of the GS (1200 h), and postgrazing (24 h after the first measurement). Herbage mass data were fitted to a model to estimate herbage disappearance rates. Herbage intake and bite mass were calculated using herbage mass disappearance and behavioral measurements. Bite rate, eating, searching, ruminating, and idling time were determined during the GS for each cow. No difference in glucose concentration was found between treatments. Concentrations of NEFA and ghrelin were the greatest for cows in the 1 x 8 treatment. Daily herbage intake did not differ between treatments; however, during the GS 1 x 8 had a greater herbage intake than 2 x 4 and CTL. Bite mass differed between treatments and throughout the GS. Bite mass was smallest for CTL during the first 60 min and greatest during the last 90 min, when cows in the 2 x 4 treatment had the smallest bite mass. Cows in 1 x 8 spent the longest time eating and the least time searching and ruminating. Eating time was greatest for 1 x 8 during the first 60 and last 90 min of the GS. Searching time only differed in the second 60 min, when it was the lowest for 1 x 8. Cows from all treatments did not ruminate during the first 120 min. Cows in CTL had the greatest rumination time during the last 90 min. The model fitted to represent dynamics of herbage mass disappearance presented differences in the fractional herbage disappearance rate. There was an interaction between treatment and time in herbage depletion rate. The results of this study present a fuller picture of foraging dynamics during the first 4 h of grazing and its potential relationship with physiological markers of hunger as affected by grazing management.
|Mastication of almonds: effects of lipid bioaccessibility, appetite, and hormone response.|
Bridget A Cassady, James H Hollis, Angie D Fulford, Robert V Considine, Richard D Mattes
The American journal of clinical nutrition 89 794-800 2009
BACKGROUND: Epidemiologic and clinical data indicate that nuts can be incorporated into the diet without compromising body weight. This has been attributed to strong satiety properties, increased resting energy expenditure, and limited lipid bioaccessibility. OBJECTIVE: The role of mastication was explored because of evidence that the availability of nut lipids is largely dependent on the mechanical fracture of their cell walls. DESIGN: In a randomized, 3-arm, crossover study, 13 healthy adults (body mass index, in kg/m(2): 23.1 +/- 0.4) chewed 55 g almonds 10, 25, or 40 times. Blood was collected and appetite was monitored during the following 3 h. Over the next 4 d, all foods were provided, including 55 g almonds, which were consumed under the same chewing conditions. Complete fecal samples were collected. RESULTS: Hunger was acutely suppressed below baseline (P 0.05), and fullness was elevated above baseline longer (P 0.05) after 40 chews than after 25 chews. Two hours after consumption, fullness levels were significantly lower and hunger levels were significantly higher after 25 chews than after 10 and 40 chews (P 0.05). Initial postingestive glucagon-like peptide-1 concentrations were significantly lower after 25 chews than after 40 chews (P 0.05), and insulin concentrations declined more rapidly after 25 and 40 chews than after 10 chews (both P 0.05). Fecal fat excretion was significantly higher after 10 chews than after 25 and 40 chews (both P 0.05). All participants had higher fecal energy losses after 10 and 25 chews than after 40 chews (P 0.005). CONCLUSION: The results indicate important differences in appetitive and physiologic responses to masticating nuts and likely other foods and nutrients. This trial was registered at clinicaltrials.gov as NCT00768417.
|Long-term infusions of ghrelin and obestatin in early lactation dairy cows.|
J R Roche, A J Sheahan, L M Chagas, D Blache, D P Berry, J K Kay
Journal of dairy science 91 4728-40 2008
Ghrelin is an endogenous ligand of the growth hormone secretagogue receptor and a potential orexigenic agent in monogastrics and ruminants. Obestatin has been reported to have the opposite (anorexigenic) effect. Fifty one multiparous cows were randomly allocated to 1 of 3 groups (n = 17): a control group and 2 groups with cows continuously infused with 0.74 mumol/d of ghrelin (GHR group) or obestatin (OBE group) subcutaneously. Infusions began 21 d in milk, and treatments continued for 8 wk. Generalized linear models were used to determine the treatment effect on average daily and cumulative milk production and composition, and plasma ghrelin, growth hormone, insulin-like growth factor (IGF)-1, leptin, nonesterified fatty acids, and glucose. Mixed models, with cow included as a repeated effect, were used to determine if treatment effects differed by week postcalving for milk production, body weight, and body condition score (BCS; scale 1 to 10). Parity, breed, week of the year at calving, treatment, week postcalving, and the 2 wk preexperimental average of each measure (covariate) were included as fixed effects. Treatment did not affect dry matter intake. Cows infused with GHR lost more BCS (-0.71 units) over the 8-wk study period than the control (-0.23 BCS units) cows, and on average were thinner than cows in either of the other 2 treatments (0.2 BCS units). Consistent with the extra BCS loss in GHR cows, plasma IGF-1, glucose, and leptin concentrations were reduced and plasma nonesterified fatty acid concentrations were greater in GHR cows. Despite a numerical tendency for GHR cows to produce more milk (1,779 kg) than control (1,681 kg) or OBE (1,714 kg) cows during the 8-wk period, milk production differences were not statistically different. However, the timing of the numerical separation of the lactation curves coincided with the significant changes in BCS, IGF-1, and leptin. Results indicate a positive effect of ghrelin infusion on lipolysis. Further research is required to determine if the numerical increase in milk production, which coincides with the increased negative energy balance, is real.
|Short communication: change in plasma ghrelin in dairy cows following an intravenous glucose challenge.|
J R Roche, A J Sheahan, L M Chagas, R C Boston
Journal of dairy science 91 1005-10 2008
Ghrelin is an endogenous ligand of the growth hormone secretagogue receptor and a potent orexigenic (appetite-stimulating) agent in humans and rodents, but little is known about its effect in dairy cows. Ten multiparous dairy cows 35 d in milk were subjected to an i.v. glucose challenge (300 mg of D-glucose/kg of body weight). Before infusion and at regular intervals after infusion, plasma glucose, insulin, nonesterified fatty acids (NEFA), growth hormone, epinephrine, and ghrelin concentrations were monitored. Plasma insulin rose (27.2 mU/L at 10 min) and NEFA, epinephrine, and ghrelin declined (nadir = 0.22 mmol/L, 22.2 microg/L, and 272 microg/L at 31, 13, and 22 min, respectively) after the glucose infusion. Ghrelin declined for 22 min before returning to suprabasal levels at approximately 75 min postinfusion. Sequential changes of the hormones and metabolites suggested a glucose transporter, type 2- and glucose transporter, type 4-mediated disposal of glucose, and an insulin-mediated reduction in NEFA. Ghrelin and epinephrine declined after glucose infusion and before the insulin peak, but the effect of insulin as a controlling factor in the hyperglycemic reduction in these hormones cannot be discounted. The post-nadir surge in ghrelin may be regulated by the decline in circulating concentrations of glucose and NEFA (an energy-deficit signal). The profile of change in plasma ghrelin in lactating dairy cows after a glucose challenge was similar to that in monogastric animals.
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|ELISAs, RIAs & GyroMark HT Assays|
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|Quality Control Ranges: Active Ghrelin RIA Kit|
|Full Service Custom-built Assays (MilliporeSigma)|
|What is the difference between active and total Ghrelin RIAs/ELISAs?||The active assays require the intact octanoyl group on the 3rd AA which means samples need to be acidified and treated with aprotinin, while total/desacyl assays can read the truncated form without the octanoyl modification.|