RIAKEY hGH IRMA Tube II

INTENDED USE : RIAKEY hGH IRMA is an in vitro diagnostic assay for the quantitative determination of human growth hormone in serum.

INTRODUCTION

Human Growth Hormone (hGH, somatotropin) is the most abundantly secreted, circulating pituitary hormone. It is synthesized by the alpha cells of the anterior pituitary, with molecular weight of about 21.5 kDa. It is composed of a polypeptide chain of 191 amino acids with two disulfide bonds. Endogenous circulating hGH has a short half-life (20-30 minutes) and its serum levels are influenced by several factors: hypoglycemia, exercise and some amino acids (arginine) result in increased hGH levels, while glucose and cortisol tend to inhibit circulating hGH. Somatotropin activity is not directed towards a specific target organ, although hGH receptors have been demonstrated both on liver cells and on lymphocyte membranes. Human Growth Hormone has a direct anti-insulin action, by facilitating amino acid transport as well as free fatty-acid release in muscle tissue. Growth in children is mediated by hGH, which stimulates the liver to produce somatomedins (or insulin-like growth factors, IGF). IGFs are low molecular weight hormones (about 7 kDa) sharing structural homology with pro-insulin. IGFs mostly circulate bound to carrier proteins, which prolong their half-life and make their serum concentrations relatively stable. Quantitative hGH testing is a necessary diagnostic tool for pathologies such as: acromegaly, gigantism, hyposomatism and hypopituitary syndromes. Basal hGH levels are of little relevance, while useful information can be obtained with several dynamic tests like: provocation with arginine, insulin, L-dopa or glucagon, and inhibition by oral glucose intake.

PRINCIPLE OF THE ASSAY

The present method is based upon two anti-hGH monoclonal antibodies recognizing two different epitopes of the molecule. One antibody is adsorbed the solid phase (coated tube), the other - labeled with Iodine 125 - is used as conjugate. During the incubation, the sample to be tested and the labeled antibody are incubated simultaneously in the coated tube forming a "sandwich". At the end of the incubation, the unbound material is removed by an aspiration/washing cycle. The radioactivity in the tubes is measured in a gamma counter.

USE PRECAUTION

• Do not use mixed reagents from different lots.
• Do not use reagents beyond the expiration date.
• Use distilled water stored in clean container.
• Use an individual disposable tip for each sample and reagent, to prevent the possible cross-contamination among the samples.
• Store the unused coated tubes at 2~8ºC in the appropriate bags with silica gel and accurately sealed.
• If large quantity of assay would be performed at one time, there might be substantial time variation between 60 tubes at one time to minimize time variation. Also, do not exceed 10 minutes for entire pipetting.
• Wear disposable globes while handling the kit reagents and wash hands thoroughly afterwards.
• Do not pipette by mouth.
• Do not smoke, eat or drink in areas where specimens or kit reagents are handle.
• Handle samples, reagents and loboratory equipments used for assy with extreme care, as they may potentially contain infectious agents.
• When samples or reagents happen to be split, wash carefully with a 3% sodium hypochlorite solution.
• Dispose of this cleaning liquid and also such used washing cloth or tissue paper with care, as they may also contain infectious agents.
• Avoid microbial contamination when the reagent vial be eventually opend or the contents be handled.
• Use only for IN VITRO.