TY - JOUR
T1 - Insulin-like growth factor binding proteins from cultured human fibroblasts. Characterization and hormonal regulation
AU - Conover, C. A.
AU - Liu, F.
AU - Powell, D.
AU - Rosenfeld, R. G.
AU - Hintz, R. L.
PY - 1989
Y1 - 1989
N2 - Specific, high affinity insulin-like growth factor (IGF) binding proteins are secreted by human fibroblasts in culture. By multiple criteria, the species of IGF binding proteins produced by human fibroblasts are distinct from the HepG2/amniotic fluid IGF binding protein, but share many characteristics with the growth hormone-dependent IGF binding protein forms predominant in normal adult human plasma. Treatment of cultured human fibroblasts with growth hormone produced an increase in IGF binding protein activity in the medium, while addition of glucocorticoids markedly diminished IGF binding activity. Insulin, epidermal growth factor, platelet-derived growth factor, and progesterone had no effect on IGF binding activity in fibroblast media. In comparison, HepG2 IGF binding activity was enhanced by progesterone, decreased by insulin, and unaffected by growth hormone or glucocorticoid treatment. Five molecular forms of IGF binding proteins were identified by Western ligand blots in human fibroblast conditioned medium, with M(r) = 41,500, 37,000, 32,000, 28,000, and 23,000. In human fibroblast conditioned medium, the M(r) = 41,500 and 37,000 IGF binding protein species were abundant, as in normal human plasma, with a major M(r) = 23,000 form which was a minor component in plasma.
AB - Specific, high affinity insulin-like growth factor (IGF) binding proteins are secreted by human fibroblasts in culture. By multiple criteria, the species of IGF binding proteins produced by human fibroblasts are distinct from the HepG2/amniotic fluid IGF binding protein, but share many characteristics with the growth hormone-dependent IGF binding protein forms predominant in normal adult human plasma. Treatment of cultured human fibroblasts with growth hormone produced an increase in IGF binding protein activity in the medium, while addition of glucocorticoids markedly diminished IGF binding activity. Insulin, epidermal growth factor, platelet-derived growth factor, and progesterone had no effect on IGF binding activity in fibroblast media. In comparison, HepG2 IGF binding activity was enhanced by progesterone, decreased by insulin, and unaffected by growth hormone or glucocorticoid treatment. Five molecular forms of IGF binding proteins were identified by Western ligand blots in human fibroblast conditioned medium, with M(r) = 41,500, 37,000, 32,000, 28,000, and 23,000. In human fibroblast conditioned medium, the M(r) = 41,500 and 37,000 IGF binding protein species were abundant, as in normal human plasma, with a major M(r) = 23,000 form which was a minor component in plasma.
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U2 - 10.1172/JCI113968
DO - 10.1172/JCI113968
M3 - Article
C2 - 2466052
AN - SCOPUS:0024560417
SN - 0021-9738
VL - 83
SP - 852
EP - 859
JO - Journal of Clinical Investigation
JF - Journal of Clinical Investigation
IS - 3
ER -