TABLE 2.

Effect of hypoxia in the presence (β-gal) or absence (Cre) of HIF-1α on 4-hydroxyproline formation in cultured newborn mouse growth plate chondrocytes

The cells were cultured in the presence of [³H]proline in normoxia or hypoxia for 24 h, and collagen synthesis was analyzed by radiochemical determination of the amount of 4-hydroxy[³H]proline formed in nondialysable proteins, i.e. mainly collagens, of the cell lysates and culture media.

Cell culture conditions	Relative hydroxyproline amount
	Cell lysates	Culture medium
	%
Experiment 1
β-Gal HIF-1af/f, normoxia	100	100
β-Gal HIF-1af/f, hypoxia	37	74
Cre HIF-1af/f , hypoxia	6	28
Experiment 2
β-Gal HIF-1af/f, normoxia	100	100
β-Gal HIF-1af/f, hypoxia	53	57
Cre HIF-1af/f , hypoxia	33	29