A Surgically Induced Low Aldosterone Rat Model

The adrenal gland produces and secretes various hormones including aldosterone and corticosterone from the zona glomerulosa and zona fasiculata of the adrenal cortex, respectively. Corticosterone is important in the regulation of blood glucose, the ability to handle stress, and maintaining normal immune function. Aldosterone results in the retention of sodium and excretion of potassium causing water retention, a greater blood volume, and an increase in blood pressure (hypertension). Aldosterone\u27s role in hypertension has previously been studied using receptor blocking agents or via complete adrenalectomy (removal of both adrenal glands). Complete adrenalectomy removes all hormones produced by the adrenal gland, and often results in death. This study compares two methods for producing a surgically induced low aldosterone model for the study of hypertension that preserves the function of the lower adrenal layers. Methods: Male spontaneous hypertensive rats (SHR) 10-19 weeks of age were randomly subjected to either a sham (incisions were made and closed) or experimental surgery, in which the right adrenal gland was removed and the outermost layer of the left adrenal gland was destroyed by freezing using two separate techniques. In the first technique, each section of the adrenal surface was frozen three times in succession until the entire gland was covered. The second technique involved freezing each section twice in succession until the entire gland was covered and the procedure was repeated a second time. Blood was drawn to be . analyzed for aldosterone and corticosterone levels using radioimmunoassay (RIA) and enzymelinked immunosorbent assay (ELISA), respectively