Collagen phenotypes during development and regression of myocardial hypertrophy in spontaneously hypertensive rats.
 The myocardium contains collagen matrix that is a major determinant of its architecture, structural integrity, and mechanical properties.
 This fibrillar matrix consists primarily of type I and type III collagens having epimysial, perimysial, and endomysial components.
 The present study shows the alteration of collagen phenotypes during the evolution of hypertensive hypertrophy.
 Therapy with captopril, an angiotensin-converting enzyme inhibitor that regresses cardiac hypertrophy, not only reduces the total amount of collagen but reverses the altered distribution of type I and type III collagen.
 In normotensive rats, captopril did not significantly reduce collagen content or alter the ratio of type I to type III collagen.
