Effect of Pregnancy on the Biosynthesis of Collagen and Proteoglycan by Normotensive or Hypertensive Rat Aortas

Abstract

The rates of biosynthesis of collagen and glycosaminoglycan were reduced in aortas of normotensive pregnant rats as compared with those of non pregnant animals of the same age. Induction of renal hypertension caused a two to three fold increase in the synthesis of aortic collagen and glycosaminoglycan in non pregnant as well as in pregnant rats. The activities of prolyl-4-hydroxylase and galactosylhydroxylysyl-glucosyltransferase, two intracellular enzymes of collagen synthesis, exhibited changes which paralleled those of collagen synthesis. Prolyl-4-hydroxylase was localized predominantly to the aortic smooth muscle cells indicating that these cells are responsible for the deposition of collagen in normal and hypertensive arteries. No shift of types I and III collagen synthesis was observed during pregnancy or in the early phases of induced renal hypertension.