Variability of serum human growth hormone levels in different commercial assays: specificity of growth hormone-releasing hormone stimulation.
Serum human growth hormone (hGH) levels were measured with three different commercial kits, comprising a radioimmunoassay (RIA) (bioMérieux, Marcy-l'Etoile, France, 'bmpoly') and two immunoradiometric assays (IRMA) (bioMérieux, 'bmmono', and CIS bioInternational, Gif-sur-Yvette, France, 'cismono'). Samples were collected after various stimulation tests [arginine-insulin, growth hormone-releasing hormone (GHRH), L-dopa and glucagon-beta-axolol] from children who were undergoing evaluation for short stature. Values obtained with the IRMAs were consistently lower than those obtained with the RIA. Furthermore, the cismono/bmmono and cismono/bmpoly values ratios were always significantly higher when samples were collected during GHRH stimulation than during the other stimulation tests. These data indicate that GHRH could induce a particular form of hGH molecule (in nature or in amount), recognized by the monoclonal antibodies in the cismono kit and that a specific form of hGH may be released by GHRH stimulation.
Chevenne
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D
Service de Biochimie-Hormonologie, Hôpital Robert-Debré, Paris, France.
Beau
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N
Léger
J
J
Porquet
D
D
D002648:Child; D005260:Female; D013006:Growth Hormone / Q000097:blood*; D013007:Growth Hormone-Releasing Hormone / Q000097:blood; D006801:Humans; D015592:Immunoradiometric Assay / Q000379:methods; D008297:Male; D011863:Radioimmunoassay / Q000379:methods; D011933:Reagent Kits, Diagnostic; D012016:Reference Values
D011933:Reagent Kits, Diagnostic; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone