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A RECEPTOR ASSAY FOR SOMATOMEDIN‐LIKE ACTIVITY USING MULTIPLICATION‐STIMULATING ACTIVITY (MSA) AS RADIOLIGAND
Author(s) -
Brinsmead MW,
Liggins GC
Publication year - 1978
Publication title -
australian journal of experimental biology and medical science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0004-945X
DOI - 10.1038/icb.1978.58
Subject(s) - somatomedin , sephadex , endocrinology , receptor , radioligand , acromegaly , medicine , chemistry , hormone , growth hormone , biology , biochemistry , enzyme
Summary 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 125 I‐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 125 I‐MSA from the placental receptor. The mean λ (precision) was 0·063, sensitivity was < 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.