title: A receptor assay for somatomedin-like activity using multiplication-stimulating activity (MSA) as radioligand.
abstract: Multiplication-stimulating activity (MSA) in the medium of cultured rat liver cells was purified 120-fold by chromatography on Dowex 50W and Sephadex G 50. MSA was labelled with 125I-iodine and bound to a human placental membrane receptor. An assay for somatomedin-like receptor activity (SmLRA) in unextracted serum was based on the displacement of 125I-MSA from the placental receptor. The mean lambda (precision) was 0.063, sensitivity was less than 0.006 SmLRA units and interassay variation was 18%. The mean (+/- S.D.) SmLRA concentrations in 13 normal subjects, 7 growth hormone deficient patients and 8 patients with active acromegaly were 0.86 +/- 0.19, 0.34 +/- 0.08 and 2.34 +/- 0.82 U/ml, respectively. This assay may have potential clinical application in disorders of growth hormone secretion.
mesh_terms: D000172:Acromegaly / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000818:Animals; D002356:Cartilage / Q000378:metabolism; D002648:Child; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D013006:Growth Hormone / Q000172:deficiency; D006801:Humans; D007016:Hypophysectomy; D008099:Liver / Q000378:metabolism; D008297:Male; D010455:Peptides / Q000494:pharmacology*; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D011485:Protein Binding; D011869:Radioligand Assay; D051381:Rats; D011972:Receptor, Insulin / Q000378:metabolism; D013002:Somatomedins / Q000378:metabolism*; D013431:Sulfates / Q000378:metabolism; D013552:Swine; D013936:Thymidine / Q000378:metabolism
chemical_list: D010455:Peptides; D013002:Somatomedins; D013431:Sulfates; D013006:Growth Hormone; D011972:Receptor, Insulin; D013936:Thymidine