Effects of Surgically-Induced Low Aldosterone on Blood Pressure of Rats

This research examined the role between the hormone aldosterone and blood pressure in spontaneously hypertensive rats (SHR) and the genetically related normotensive Wistar-Kyoto (WKY) rats. Aldosterone is a hormone produced in the outer layer of the adrenal cortex, which is largely responsible for regulation of blood sodium and potassium ion concentrations. Aldosterone causes the kidneys to retain more sodium within the body. The blood sodium ion concentration is directly responsible for blood volume. When more sodium is retained in the body, more water is retained by the kidneys, balancing ion concentration. This increase in water retention increases blood volume and blood pressure. This research was designed determine if a long-term link exists between blood pressure and aldosterone levels, leading to a better understanding of cardiovascular development and the development of hypertension. Using five to six-week-old male and female rats, surgical operations consisted of either an adrenal freezing procedure or a sham operation. For the adrenal-frozen rats, the outer adrenal cortex was frozen on one of the glands, and the other gland was completely removed. Sham operations did not involve any changes to the adrenal glands. All rats were then allowed two weeks to recover. From 7 to 23 weeks of age, biweekly measurements were taken of weight, systolic blood pressure, and heart rate. No significant difference was found between adrenal frozen and sham treated male and female SHR in systolic blood pressure, heart rate, or weight gain. Data collection for WKY rats is ongoing