Immunofunctional assay of human growth hormone (hGH) in serum: A possible consensus for quantitative hGH measurement.

摘要

Confirmation of the diagnosis of GH deficiency in adults and chil- with labeled streptavidin. The assay is sensitive (detection range,dren involves provocative testing for human (h) GH. Different com- 0.1-100 Fg/L) and has average inter- and intraassay precisions ofmercially available immunoassays yield largely discrepant results in 10.3% and 7.3%, respectively. Endogenous GH-binding protein doesthe measurement of GH levels in human serum. These discrepancies not interfere with the hGH resu placental lactogen shows no deresultin doubtful relevance of cut-off levels proposed for GH provoc- tectable cross-reaction in this immunofunctional assay. The degree ofative testing. We have developed an immunofunctional assay method immunofunctionally active hGH forms in serum samples, calculatedthat allows quantitation of only those GH forms in circulation that by comparison of immunofunctional assay and RIA results, variedpossess both binding sites of the hormone for its receptor and thus can between 52-93%‘. We propose this immunofunctional assay for GHinitiate a biological signal in target cells. An anti-hGH monoclonal measurement as a new reference method for hGH quantitation inantibody recognizing binding site 2 of hGH is immobilized and used serum. The immunofunctional assay translates only hGH forms intoto capture hGH from the serum sample. Biotin-labeled recombinant an assay signal that are capable of dimerizing GH receptors and, thus,GH-binding protein in a second incubation step forms a complex with ofinitiating a biological effect in target cells.