This research project is designed to determine whether taurine when administered in combination with either calcium or tryptophan is important in preventing or lowering blood pressure. Deoxycorticosterone acetate salt uninephrectomized hypertensive, renal (bilateral kidney encapsulated) hypertensive and spontaneously hypertensive rats and the appropriate normotensive control rats will be used in the proposed project. Four experiments have been outlined. Weekly body weights and blood pressures will be recorded to monitor growth and level of systolic blood pressure. Food and fluid intakes will be measured to determine how much of the chemical is getting into the body. Renal function and electrolyte excretion will be assessed. Heart rate will be measured to assess the effect of taurine and calcium or taurine and tryptophan intake on sympathetic outflow to the periphery. Resting colonic temperature will be measured to determine whether taurine administration will result in hypothermia. The dipsogenic responsiveness to isoproterenol, a beta- adrenergic agonist and angiotensin II will be tested. At sacrifice, each rat will have direct measurements of heart rate, systolic, mean and diastolic blood pressures via cannulation of the carotid artery. Each rat will then be exsanguinated, the blood collected, centrifuged and analyzed for serum concentrations of calcium, sodium, potassium, creatinine, and urea nitrogen. The heart, thyroid, adrenal, and kidneys will be removed and weighed. All data will be analyzed for statistical significance on an Apple II-e computer using one-way and two-way analyses of variance with repeated measures. Post hoc differences among groups will be determined using the Newman-Keuls multiple range test. Significance will be set at the 95% confidence limit.
