Differential regulation of serum growth hormone (GH)-binding protein during continuous infusion versus daily injection of recombinant human GH in GH-deficient children.

1993 ◽  
Vol 76 (5) ◽  
pp. 1135-1139 ◽  
Author(s):  
M Tauber ◽  
H De Bouet Du Portal ◽  
B Sallerin-Caute ◽  
P Rochiccioli ◽  
R Bastide
1993 ◽  
Vol 129 (6) ◽  
pp. 559-564 ◽  
Author(s):  
Guy Massa ◽  
Mapoko Ilondo ◽  
Magda Vanderschueren-Lodeweyckx

The characteristics of the human serum growth hormone-binding protein (GHBP) were compared with those of a water-soluble GH-binding site prepared by incubating cultured IM-9 lymphocytes in assay buffer with 25 mmol/l iodoacetamide. High-performance liquid chromatography gel filtration of the water-soluble GH-binding site incubated with 125I-labeled human GH ([125I]hGH) revealed a large peak of bound [125I]hGH eluting at the same position as the peak of [125I]hGH bound to the GHBP in serum. The estimated Mr of the peak was 120 000, presumably representing one [125I]hGH bound to two binding sites. The binding specificities of the serum GHBP, the water-soluble GH-binding site and the GH receptor on IM-9 lymphocytes were identical. The binding affinities for 22 000 hGH and for 20 000 hGH of the serum GHBP were similar to the binding affinity of the water-soluble GH-binding site but lower than those of the cellular GH receptor. These findings show that the characteristics of the serum GHBP are comparable to those of the water-soluble GH-binding site released from IM-9 cells and support the hypothesis that in man the serum GHBP is produced by proteolytic cleavage of the cellular GH receptor.


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