Plasma renin activity in heart failure-prone SHHF/Mcc-facp rats.

Plasma renin activity (PRA) increases during heart failure; however, PRA is altered by drug therapy, and it is difficult to study the natural progression of elevated PRA in humans and the possible factors that contribute to its rise. This study evaluated PRA in a drug-naive hypertensive rat model (SHHF/Mcc-facp) that has a genetic program resulting in heart failure (HF). Mean arterial blood pressure and PRA were determined and correlated to heart weight index in conscious normotensive, spontaneously hypertensive rats and HF rats of various ages. PRA, atrial natriuretic peptide, and aldosterone levels progressively increase with age in male HF rats. PRA and blood pressure are independently correlated to cardiac hypertrophy in male HF rats. Atrial natriuretic peptide was elevated in spontaneously hypertensive compared with normotensive rats. Female HF rats have elevated PRA, but the increase is temporally delayed compared with that in male HF rats. Hypertension, PRA, and male gender are independent factors contributing to cardiac hypertrophy and heart failure in the HF model. The HF rat model may prove useful in determining the contribution of these factors in the progression from cardiac hypertrophy to heart failure.