A2074 FAILURE OF SUPPRESSION OF THE RENIN ANGIOTENSIN ALDOSTERONE SYSTEM A POSSIBLE MECHANISM OF ESSENTIAL HYPERTENSION

Abstract

Objectives: To compare changes in blood pressure (BP), insulin, angiotensin II (AngII) and aldosterone in obese and nonobese patients with essential hypertension after intake of oral glucose with NaCl. Methods: 20 newly diagnosed untreated essential hypertensive patients were studied. Smokers and those with diabetes, cardiac or renal disease or taking medications excluded. Patients fasted overnight (8- 10 hrs) then each subject took 75gm glucose plus 3 gm NaCl dissolved in 250 ml. Patients were monitored for 2 hours. Half hourly BP, plasma glucose (PG), serum electrolytes (Na+, K+), insulin, AngII and aldosterone were measured. Results: Subjects were classified into obese (MBI > 30 Kg/m2) (n = 11) and nonobese (MBI < 30 Kg/m2) (n = 9). In both groups, diastolic BP decreased significantly with no significant change in systolic BP. Serum K+ decreased significantly in obese and nonobese patients. A significant increase in serum Na+ occurred in obese patients only at 30 minutes (P = .02) and it was significantly higher in obese hypertensives compared with nonobese (P = .04). In nonobese hypertensive patients serum Na+ correlated positively with plasma glucose (P = .003) and serum insulin (P = .005). In both groups AngII levels did not change significantly. In obese patients aldosterone level decreased significantly and it showed significant positive correlation with systolic (P = .05), diastolic (P = .009) and mean BP (P = .01). In nonobese patients aldosterone levels showed no significant change. However, aldosterone levels were significantly higher in nonobese than obese patients (P = .02). Conclusion: Failure of suppression of AngII in both hypertensive groups by NaCl load and aldosterone in nonobese patients by decrease in serum K+ may indicate failure of suppression of renin angiotensin aldosterone system in hypertensive patients.