Changes in ventricular creatine-kinase with progression and regression of cardiac hypertrophy in hypertensive rats.

We studied the distribution of four isoenzymes of creatine-kinase (MM, MB, BB and the mitochondrial) in 13 renovascular hypertensive rats and five age-matched controls. After 6 weeks of hypertension, seven rats were treated with captopril (2 mg/kg daily) for 4 weeks and the other six were left untreated for 4 weeks. After the rats were killed an adaptive increase in MB and BB was found at the expense of MM in the hypertensive rats compared with the controls. The captopril-treated rats displayed persistently higher levels of both MB and BB than the controls. Therefore, the regression in cardiac hypertrophy that is achieved by captopril is accompanied by persistence of the isoenzymic pattern that leads to better use of energy-rich phosphates.