Cross-reaction of serum somatomedin-binding protein in a radioimmunoassay developed for somatomedin-binding protein isolated from human amniotic fluid.
A radioimmunoassay was developed for somatomedin-binding protein isolated from human amniotic fluid. The mean level in amniotic samples from 20-22 week of gestation was high, 51 micrograms/ml. Human serum and serum fraction gave dose-response curves superimposable on that for the pure amniotic binding protein. Gel chromatography of serum at neutral pH disclosed immunoreactive binding protein only in fractions with a molecular size of 35 000 corresponding to elution volume for the low molecular form somatomedin-binding protein. The mean levels (mean and range) of immunoreactive somatomedin-binding protein in cord blood (191 ng/ml, 55-1698 ng/ml) and in diabetic patients with uraemia (97 and 51-174 ng/ml) were 5- to 10-fold elevated above those of healthy adults (23 and 18-36 ng/ml). In acromegaly the levels decreased with increasing GH production (r = -0.77; P less than 0.005). In adult patients with GH deficiency the levels were 2-fold elevated in comparison with healthy subjects. Apart from patients with uraemia a negative correlation was found in adults between the levels of immunoreactive binding protein and immunoreactive IGF-I which reflect the GH production (r = -0.81, P less than 0.001).
D000172:Acromegaly / Q000097:blood; D000293:Adolescent; D000328:Adult; D000368:Aged; D000653:Amniotic Fluid / Q000032:analysis; D002352:Carrier Proteins / Q000276:immunology* / Q000302:isolation & purification; D002850:Chromatography, Gel; D003429:Cross Reactions; D003920:Diabetes Mellitus / Q000097:blood; D005260:Female; D013006:Growth Hormone / Q000172:deficiency; D006801:Humans; D007328:Insulin / Q000032:analysis; D018969:Insulin-Like Growth Factor Binding Proteins; D008875:Middle Aged; D010455:Peptides / Q000032:analysis; D011247:Pregnancy; D011863:Radioimmunoassay / Q000379:methods*; D013002:Somatomedins / Q000032:analysis; D014511:Uremia / Q000097:blood
D002352:Carrier Proteins; D007328:Insulin; D018969:Insulin-Like Growth Factor Binding Proteins; D010455:Peptides; D013002:Somatomedins; D013006:Growth Hormone