In this study, we have characterized the influence of hypoxia on the expression of hydroxylases crucially involved in col-lagen fiber formation, such as prolyl-4-hydroxylases (Ph4) and procollagen lysyl-hydroxylases (PLOD). Using the rat vascular smooth muscle cell line A7r5, we found that an hypoxic atmosphere caused a characteristic time-dependent five- to 12-fold up-regulation of the mRNAs of the two P4h a-subunits [aI (P4ha1) andaII (P4ha2)] and of two lysyl-hydroxylases (PLOD1 and PLOD2).
