Biochemical changes associated with development and reversal of cardiac hypertrophy in spontaneously hypertensive rats.

This study is the first report describing the sequence of biochemical alterations of myocardium during the progression of naturally occurring hypertrophy in spontaneously hypertensive rats (SHRs) and then with its reversal by alpha-methyldopa therapy. Changes in DNA, RNA, hydroxyproline, as well as incorporation of 14C lysine into cardiac myosin, were compared with the pattern found in suitably matched controls. A significant increase in RNA, hydroxyproline, and 14C incorporation was observed in SHRs. Antihypertensive treatment caused reversal of hypertrophy and normalization of all biochemical parameters except hydroxyproline, the concentration of which increased significantly as myocardial weight decreased. These compositional changes may help explain the conflicting result of the haemodynamic effects of cardiac hypertrophy.