Effect of ovariectomy in heart failure-prone SHHF/Mcc-fa(cp) rats

The importance of the loss of ovarian function to the progression of hypert ension and heart disease in women is controversial. We investigated whether ovariectomy would accelerate development of hypertension, congestive heart failure, and neurohumoral activation in adult spontaneous hypertension hea rt failure (SHHF) rats, a genetic model of heart failure. Six months after ovariectomy, no significant differences between central and ovariectomized rats were seen in systolic or diastolic blood pressure, left ventricular fr actional shortening by echocardiography, or heart weight. Percent V-1 myosi n isozyme was significantly lower in ovariectomized rats. Northern blot ana lysis failed to show significant differences between groups in expression o f hepatic angiotensinogen, renal renin, or left ventricular atrial or brain natriuretic peptide mRNA. In a second experiment, serial measures of systo lic pressure and left ventricular shortening fractions failed to document a significant difference between control and ovariectomized rats as they dev eloped heart failure, although there was a significant decline in shortenin g fraction in both groups at the age when regular estrous cycling naturally ceases. Survival time was similar between groups. In summary, ovariectomy of adult SHHF rats does not appear to affect the progression of genetically programmed hypertension and heart failure in this model.