Circadian variation of aldosterone urinary excretion in idiopathic hypertension

Daily variations of the urinary aldosterone excretion have been studied in 8 hypertensive and in 4 normotensive women. The examined subjects did not receive any drug for at least two weeks before the study and were under the same standardized life-conditions. The urine samples were collected every 3 h for two consecutive days. Population mean cosinor analysis by Halberg did not yield a statistically significant rhythm of aldosterone urinary excretion in the hypertensive group. Further investigation of the temporal structure of the renin-angiotensin-aldosterone system is therefore necessary.