Human Growth Hormone ELISA Kit

Sample

Serum and plasma

Species Reactivity

Human

Detection Method

sELISA

Intended Use

The Human Growth Hormone ELISA Kit is intended to be used for quantitative measurement of human growth hormone ELISA Kit in human serum and plasma for research purposes.
In addition to serum and plasma samples, hGH can be determined in other human body fluids and in cell culture supernatants of various human cell lines for research purposes

Contents of Kit

1. Microtiter plate: ready for use, coated with rabbit-anti-hGH-antibody. Wells are separately breakable. (8x12) wells
2. Calibrators (CAL A-E): lyophilized, (recombinant human GH), concentrations are given on vial labels and on quality certificate. 5 x 750 μL
3. Control (CTR): lyophilized, (human serum), concentration is given on quality certificate. 1 x 500 μL
4. Antibody Conjugate (DET): ready for use, contains rabbit biotinylated anti-hGH antibody. 1 x 12 mL
5. Enzyme Conjugate (EC): ready for use, contains HRP (Horseradish-Peroxidase)-labelled Streptavidin. 1 x 12 mL
6. Dilution Buffer (DIL): ready for use. Please shake before use! 1 x 120 mL
7. Washing Buffer (WB): 20-fold concentrated solution. 1 x 50 mL
8. Substrate (S): ready for use, horseradish-peroxidase-(HRP) substrate, stabilised Tetramethylbencidine. 1 x 12 mL
9. Stopping Solution (STP): ready for use, 0.2 M sulfuric acid. 1 x 12 mL
10. Sealing Tape: for covering the microtiter plate. 2

Storage

Store the kit at 2-8°C after receipt until its expiry date. The lyophilized reagents should be stored at –20 °C after reconstitution. Avoid repeated thawing and freezing.
The shelf life of the components after initial opening is warranted for 4 weeks, store the unused strips and microtiter wells airtight together with the desiccant at 2-8°C in the clip-lock bag, use in the frame provided. The reconstituted components Calibrators A-E and Controls CTR must be stored at –20°C (max. 4 weeks). For further use, thaw quickly but gently (avoid temperature increase above room temperature and avoid excessive vortexing). Up to 3 of the freeze-thaw cycles did not influence the assay. The 1:20 diluted Washing Buffer WB is 4 weeks stable at 2-8°C

Precision

Intra-Assay Variance
One sample has been measured 14 times in the same assay. The results are shown in table below. The measured coefficient of variation (CV) is 5.46%. Intra assay variance has also been evaluated externally, two serum samples with 0.45 and 5.94 μg/L hGH were measured 10 times within the same assay. The resulting coefficients of variation were 3.65% and 2.16%.

Inter-Assay Variance
Serum samples were measured in independent assays. On average the coefficient of variation was 4.34%. Results are shown in detail in table below. Here also externally acquired data are available: The mean coefficient of variation for inter-assay variance at 2.39; 5.37 and 14.33 μg/L hGH was 5.98%; 3.93% and 3.12%, respectively.

Sensitivity

Sensitivity was assessed by measuring the blank and calculating the theoretical concentration of the blank + 2SD. The analytical sensitivity of the Human Growth Hormone ELISA Kit is 0.0115 μg/L.

General Description

The endocrine system of human Growth Hormone (hGH), also named Somatropin, is characterized by an extreme complexity. hGH is the product of the GH-1 gene located on chromosome 17 and expressed in pituitary cells. 80% of the hGH is a non-glycolsylated 22 kDa protein consisting of 191 amino acids. About 20% is a variant form of 20 kDa resulting from alternative splicing. Additionally, several smaller variants can be found in circulation as well as translational modificated proteins and different degrees of protein aggregation. Bioactivity of Growth Hormone is regulated by a specific binding protein (GHBP) formed by the extra cellular part of the cellular transmembran GH-receptor. These modifications allow a tight control of the half-life period hGH and of its bioactivity.
Not only synthesis and posttranslational modification but also secretion of hGH is tightly regulated. Spontaneous pulsatile secretion takes place with a single pulse every three hours and a maximal secretion during night's sleep. Several different stimuli as physiologic stress or hypoglycaemia result in additional hGH secretion, induced by the hypothalamic hormones Somatostatin and GH-Releasing Hormone (GHRH). Age, sexual steroids, nutritional status, illness and emotions influence the amount of secreted hGH. Because of the multitude of influencing factors, the normal quantitative secretion is not known.
Physiological functions are partially exerted by Insulin-like Growth Factors (IGFs). In children and adolescent, the hGH system is the main regulator of growth. If the hGH system fails totally, human growth will end at 120 cm. Beside regulation of growth hGH exerts an anabolic effect on muscle and connective tissue as wells as on bone and different other organs (heart, intestine). Further hGH was proved to have a lipolytic effect.
Growth Hormone pathology is characterized by extreme high or extreme low hGH secretion. During childhood it is the Growth Hormone deficiency congenital or acquired, which leads to microsomia. For diagnosis of Growth Hormone deficiency an hGH stimulation test has to be done or the spontaneous excretion must be investigated. The therapy consists of substitution of endogenous Growth Hormone by recombinant hGH resulting in normalization of growth.
In adulthood hGH deficiency is mostly caused by pituitary adenoma (and their surgical excision). hGH deficiency is associated with adipositas, muscle dystrophy, arteriosclerosis, osteoporosis, adynamia. Substitutional therapy is a well-known, approved and efficient therapy of severe Growth Hormone deficiency in adulthood. Therapeutic success is directly as well as indirectly proved by measurement of IGF in serum.
Excessive hGH secretion, mostly caused by pituitary adenoma, results in childhood in gigantism, in adulthood in acromegaly, leading to enlarged extremities, diabetes, heart insufficiency and tumor growth. Surgical excision of the adenoma is the therapy of choice. If tumor excision is not possible or incomplete, a medicinal therapy with somatostatin preparation will be conducted, resulting in inhibition of hGH production. Alternatively, hGH analoga (e.g. Pegvisomat) are used to block the hGH receptor and thereby inhibit action of endogenous hGH. Measurement of human Growth Hormone (hGH, Somatropin) is done for diagnostic of Growth Hormone deficiency or Growth Hormone excess (arcomegaly). During medicinal and/or after surgical therapy of arcomegaly Growth Hormone (and IGF-I) measurement is used for therapy control.

Standard Curve

The following data is for demonstration only and cannot be used in place of data generation at the time of assay.

The exemplary shown calibration curve in Figure below cannot be used for calculation of your test results. You have to establish a calibration curve for each test you conduct!