GHBP ELISA Assay Kit

$540.00

The Eagle Biosciences GHBP ELISA Assay Kit is for the quantitative measurement of human Growth Hormone Binding Protein levels in serum or plasma. The GHBP ELISA Assay kit is for Research Use Only.

SKU: E024 Categories: , ,

GHBP ELISA Assay Kit

For Research Use Only

Size: 1×96 wells
Sensitivity: 0.006 ng/ml
Incubation Time: 3 hours
Sample Type: Serum, Plasma
Sample Size: 15 µL

GHBP ELISA Assay Kit is manufactured by Mediagnost

Additional Information

Assay Background

Hormone Binding Protein (GHBP) consists of 238 amino acids and includes four sides for glycosylation and three disulfide bounds. In humans GHBP is formed by receptor shedding of the growth hormone receptor by a metalloprotease (ADAM17).  In equilibrium about 50% of circulating growth hormone (GH) is bound to GHBP but only 2% of the circulating GHBP bound a GH molecule with a stoichiometry of 1:1. Only in case of supraphysiological GHBP levels a 2:1 ratio appears. The complex of GH and GHBP has an approximate molecular weight of 80 kDa (GHBP 60 kDa). In an animal model (guniea pig) the complex formation increases half-life from 11-20 minutes up to about 100 minutes and in general binding to GHBP inhibits GH cellular action.

GHBP Physiology
GHBP concentration is independent of GH pulsatility and does not show a circadian rhythm. GHBP levels are low until 2-6 months of life, increase steeply in the first two years and continue to increase slowly until early adulthood. From the the 4th decade the GHBP serum concentration declines slowly.  GHBP correlates positively with the intraabdominal fat mass and is increased in type II diabetics with hyperinsulinaemi. It is not known whether the tight relationship between fat mass and circulating GHBP results from GHBP expression in adipocytes or any other mechanism.

From a diagnostic point of view undetectable GHBP levels could point to a GH insensitivity, caused by a deletion in the GH-receptor gene. Further, the IGF-I/GHBP ratio might be an indicator for GH-deficiency in adults, in particular in women. It could also be predictive for GH treatment response.  The strong positive relationship with intraabdominal fat mass might be a hint, that GHBP is a possible biomarker for the amount of visceral adipose tissue.

Assay Principle

The Eagle Biosciences GHBP ELISA Assay Kit is based on polyclonal antibodies and recombinant GHBP, expressed in eukaryotic cells.  The Eagle Biosciences GHBP ELISA is a so-called Sandwich-Assay. It utilizes two specific antibodies of high affinity. First the GHBP in the sample binds to the immobilized antibody on the microtiter plate. In a two-step sequence, the biotin-conjugated anti-GHBP-Antibody and the streptavidin-peroxidase are bound. Subsequently, the peroxidase catalyzes an enzymatic reaction resulting in a blue coloration. The intensity of the blue color depends on the GHBP content of the sample. The reaction is stopped by the addition of stop solution and color intensity is quantified by measuring the absorption. This ELISA allows secure and reproducible measurement of GHBP in human body fluids and is a suitable tool for the investigation of GHBP as biomarker in energy and fat metabolism. In a preliminary study GHBP was measured in serum of healthy blood donors and mean concentration of 16.28 ng/mL was detected (Range: 12.48 -22.31).

Specificity

The specificity of the antibodies used for GHBP detection in the Eagle Biosciences GHBP ELISA E024 was evaluated by seize exclusion chromatography analysis of human serum enriched with recombinant growth hormone (Fig 2) and subsequent analysis of SEC fractions by Eagle Biosciences E022 or GHBP antibodies.

Manual

Product Manual