Insulin-like growth factor binding proteins (IGF-BPs) in bovine articular and ovine growth-plate chondrocyte cultures: their regulation by IGFs and modulation of proteoglycan synthesis.
Biochim Biophys Acta
; 1245(1): 43-8, 1995 Aug 17.
Article
em En
| MEDLINE
| ID: mdl-7544626
ABSTRACT
Cultured chondrocytes respond to insulin-like growth factors (IGFs) by increasing the production of proteoglycans and insulin-like growth factor binding proteins (IGF-BPs). To investigate the biological effects of IGFs and IGF-BPs, isolated bovine articular and ovine growth-plate chondrocytes were cultured at high density in the presence of IGF-1, and its truncated form, des (1-3) IGF-I. Both growth factors stimulated the production of IGF-BPs in articular and growth-plate chondrocyte monolayers. Western ligand blots showed that bovine articular chondrocytes released two forms of IGF-BPs into conditioned medium with molecular weights of 29 and 31 kDa. Ovine growth-plate chondrocytes released four different forms of IGF-BPs of approx. 22, 24; 29-30 and 34 kDa. IGF-I and des (1-3) IGF-I stimulated total proteoglycan synthesis by articular chondrocytes up to 1.5-fold. The truncated analogue was more potent at lower concentrations, particularly in stimulating incorporation of newly synthesized proteoglycans into the cell-layer. The maximal stimulation of proteoglycan synthesis in ovine growth-plate chondrocyte culture was 3-fold with des (1-3) IGF-I, while IGF-I enhanced proteoglycan production by only 2-fold over the concentrations used. Our results suggest that endogenous IGF-BPs in chondrocyte cultures act as a part of a feed-back mechanism which diminishes the bioactivity of IGF-I.
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Base de dados:
MEDLINE
Assunto principal:
Fragmentos de Peptídeos
/
Proteoglicanas
/
Fator de Crescimento Insulin-Like I
/
Proteínas de Transporte
/
Cartilagem
Idioma:
En
Ano de publicação:
1995
Tipo de documento:
Article