The possible role of the renin-angiotensin system and ACTH in controlling the temporal organization of circadian rhythm of aldosterone was studied in patients with mesor-hypertension (MH) by simultaneous radioimmunological determinations of within-day changes in plasma renin, aldosterone and cortisol. Thirty-nine uncomplicated, untreated mesor-hypertensive patients, divided in subtypes, were examined. The interrelationship between the rhythm components revealed that the circadian cyclicity of aldosterone in both mesor-normotensive and mesor-hypertensive subjects, with either normal or high renin patterns, has a similar timing in acrophase with renin periodicity, which leads the circadian cortisol rhythm. In low-renin mesorhypertensive subjects a circadian rhythm of aldosterone and cortisol, but not of renin, remains demonstrable. The confidence limits of the estimated acrophase for circadian cortisol rhythm do not, however, overlap the confidence arcs of the aldosterone phase. These findings suggest that in normal or high renin MH subjects the aldosterone rhythmicity is mainly controlled by the renin-angiotensin system. Conversely in low-renin MH subjects the temporal organization of the aldosterone circadian sequences seems to be completely independent of renin-angiotensin control.

Adolescent↗

PubMedDate not supplied

'Minimal-change hypertensive retinopathy' and 'arterial pre-hypertension', illustrated via ambulatory blood-pressure monitoring in putatively normotensive subjects.

PURPOSE: To investigate the 24 h blood-pressure (BP) pattern in subjects who were found to show some incipient signs of hypertensive retinopathy but had been diagnosed as normotensives by means of casual sphygmomanometry. METHODS: Non-invasive ambulatory BP monitoring was performed in 25 caucasian subjects (16 M, 9 F; mean age 46 +/- 16 years) showing this type of retinal problem. A comparable number of controlled normotensive Caucasian subjects (15 M, 10 F; mean age: 48 +/- 15 years) without funduscopic signs of hypertensive retinopathy were investigated as a reference group. A series of BP tests over time was analysed by means of conventional biometry and chronobiological methods. RESULTS: The biometric estimates suggest that the investigated subjects with incipient hypertensive retinopathy, although characterized by BP values below 140/90 mmHg, show a significantly higher daily systolic BP. The increase, however, is within WHO reference limits and is not associated with the abolition of the circadian BP rhythm. CONCLUSIONS: The results suggest that the initial signs of hypertensive retinopathy may appear before BP elevation above WHO reference limits occurs. Because of this, it can be assumed that there is such a condition as 'minimal-change hypertensive retinopathy' associated with a haemodynamic picture of 'arterial pre-hypertension'.

Blood Pressure↗