Brain-gut peptides (BGP/Gehrelin) ELISA Kit

Antigen: Brain-Gut Peptides (BGP)

Reactivity: Mouse (Murine)

Application: ELISA

Certificates: ISO 9001:2008

Catalog no.: ABIN365507

Additional Information

Characteristics: This immunoassay kit allows for the in vitro quantitative determination of mouse Gehrelin concentrations in serum, plasma and other biological fluids.

Alternative name: Brain-gut peptides (BGP/Gehrelin)

Description: Ghrelin is a hormone produced mainly by P/D1 cells lining the fundus of the human stomach and epsilon cells of the pancreas that stimulates hunger. Ghrelin levels increase before meals and decrease after meals. It is considered the counterpart of the hormone leptin, produced by adipose tissue, which induces satiation when present at higher levels. In some bariatric procedures, the level of ghrelin is reduced in patients, thus causing satiation before it would normally occur. Ghrelin is also produced in the hypothalamic arcuate nucleus, where it stimulates the secretion of growth hormone from the anterior pituitary gland. Receptors for ghrelin are expressed by neurons in the arcuate nucleus and the ventromedial hypothalamus. The ghrelin receptor is a G protein-coupled receptor, formerly known as the GHS receptor (growth hormone secretagogue receptor). Ghrelin plays a significant role in neurotrophy, particularly in the hippocampus, and is essential for cognitive adaptation to changing environments and the process of learning. Recently, ghrelin has been shown to activate the endothelial isoform of nitric oxide synthase in a pathway that depends on various kinases including Akt. 3

Specificity: This assay recognizes recombinant and natural mouse Gehrelin. No significant cross-reactivity or interference was observed.

Application Details

Principle: The microtiter plate provided in this kit has been pre-coated with an antibody specific to Gehrelin. Standards or samples are then added to the appropriate microtiter plate wells with a biotin-conjugated antibody preparation specific for Gehrelin and Avidin conjugated to Horseradish Peroxidase (HRP) is added to each microplate well and incubated. Then a TMB (3,3',5,5' tetramethyl-benzidine) substrate solution is added to each well. Only those wells that contain Gehrelin, biotin-conjugated antibody and enzyme-conjugated Avidin will exhibit a change in color. The enzyme-substrate reaction is terminated by the addition of a sulphuric acid solution and the color change is measured spectrophotometrically at a wavelength of 450 nm ± 2 nm. The concentration of Gehrelin in the samples is then determined by comparing the O.D. of the samples to the standard curve.

Protocol: Preparation of Reagents: Bring all reagents to room temperature before use. 1. Wash Buffer If crystals have formed in the concentrate, warm up to room temperature and mix gently until the crystals have 6 completely dissolved. Dilute 20 ml of Wash Buffer Concentrate into deionized or distilled water to prepare 500 ml of Wash Buffer. 2. Standard Reconstitute the Standard with 1.0 ml of Sample Diluent. This reconstitution produces a stock solution of 1000 pg/ml. Allow the standard to sit for a minimum of 15 minutes with gentle agitation prior to making serial dilutions. The undiluted standard serves as the high standard (1000 pg/ml). The Sample Diluent serves as the zero standard (0 pg/ml). 3. Biotin-antibody Dilute to the working concentration using Biotin-antibody Diluent(1:100), respectively. 4. HRP-avidin Dilute to the working concentration using HRP-avidin Diluent(1:100), respectively. Precaution: The Stop Solution provided with this kit is an acid solution. Wear eye, hand, face, and clothing protection when using this material. Sample Collection and Storage: Serum Use a serum separator tube (SST) and allow samples to clot for 30 minutes before centrifugation for 15 minutes at 1000 g. Remove serum and assay immediately or aliquot and store samples at -20° C. Avoid repeated freeze-thaw cycles. Plasma Collect plasma using citrate, EDTA, or heparin as an anticoagulant. Centrifuge for 15 minutes at 1000 g within 30 minutes of collection. Assay immediately or aliquot and store samples at -20°C. Avoid repeated freeze-thaw cycles. Assay Procedure: Calculation of Results: Average the duplicate readings for each standard, control, and sample and subtract the average zero standard optical density. Create a standard curve by reducing the data using computer software capable of generating a four parameter logistic (4-PL) curve-fit. As an alternative, construct a standard curve by plotting the mean absorbance for each standard on the y-axis against the concentration on the x-axis and draw a best fit curve through the points on the graph. The data may be linearized by plotting the log of the Gehrelin concentrations versus the log of the O.D. and the best fit line can be determined by regression analysis. This procedure will produce an adequate but less precise fit of the data. If samples have been diluted, the concentration read from the standard curve must be multiplied by the dilution factor. 10 Limitations of the Procedure: The kit should not be used beyond the expiration date on the kit label. Do not mix or substitute reagents with those from other lots or sources. It is important that the Calibrator Diluent selected for the standard curve be consistent with the samples being assayed. If samples generate values higher than the highest standard, dilute the samples with the appropriate Calibrator Diluent and repeat the assay. Any variation in Standard Diluent, operator, pipetting technique, washing technique, incubation time or temperature, and kit age can cause variation in binding. This assay is designed to eliminate interference by soluble receptors, binding proteins, and other factors present in biological samples. Until all factors have been tested in the Immunoassay, the possibility of interference cannot be excluded.

Application Notes: 11 When mixing or reconstituting protein solutions, always avoid foaming. To avoid cross-contamination, change pipette tips between additions of each standard level, between sample additions, and between reagent additions. Also, use separate reservoirs for each reagent. When using an automated plate washer, adding a 30 second soak period following the addition of wash buffer, and/or rotating the plate 180 degrees between wash steps may improve assay precision. To ensure accurate results, proper adhesion of plate sealers during incubation steps is necessary. Substrate Solution should remain colorless until added to the plate. Keep Substrate Solution protected from light. Substrate Solution should change from colorless to gradations of blue. Stop Solution should be added to the plate in the same order as the Substrate Solution. The color developed in the wells will turn from blue to yellow upon addition of the Stop Solution. Wells that are green in color indicate that the Stop Solution has not mixed 12 thoroughly with the Substrate Solution.

Components: Reagent Quantity Assay plate 1 Standard 2 Sample Diluent 1 x 20 ml Biotin-antibody Diluent 1 x 10 ml HRP-avidin Diluent 1 x 10 ml Biotin-antibody 1 x 120µl HRP-avidin 1 x 120µl 5 Wash Buffer 1 x 20 ml (25×concentrate) TMB Substrate 1 x 10 ml Stop Solution 1 x 10 ml STORAGE 1. Unopened test kits should be stored at 2-8°C upon receipt and the microtiter plate should be kept in a sealed bag. The test kit may be used throughout the expiration date of the kit. Refer to the package label for the expiration date. 2. Opened test kits will remain stable until the expiring date shown, provided it is stored as prescribed above. 3. A microtiter plate reader with a bandwidth of 10 nm or less and an optical density range of 0-3 OD or greater at 450nm wavelength is acceptable for use in absorbance measurement.

Storage: 1. Unopened test kits should be stored at 2-8°C upon receipt and the microtiter plate should be kept in a sealed bag. The test kit may be used throughout the expiration date of the kit. Refer to the package label for the expiration date. 2. Opened test kits will remain stable until the expiring date shown, provided it is stored as prescribed above. 3. A microtiter plate reader with a bandwidth of 10 nm or less and an optical density range of 0-3 OD or greater at 450nm wavelength is acceptable for use in absorbance measurement. Expiration date: six months from the date of manufacture.

Restrictions: For Research Use only