Nocturnal Blood Pressure and Hypertension - Central and Peripheral 24-h Blood Pressure.

75 patients with hypertension and chronic kidney disease (CKD I-II) and 75 healthy subjects is examined with both central and peripheral 24 hours blood pressure monitoring, 1 night home polygraphy to determine whether the subject has obstructive sleep apnea (OSA), and if so the degree (apnea hypopnea index, AHI), blood and urine samples to determine levels of urine aquaporine2 (u-AQP2), urine endothelial sodium channel (u-EnaC), plasma renin concentration (PRC), plasma angiotensin II (p-AngII), plasma aldosterone (p-aldosterone), plasma vasopressin (p-AVP) and plasma endothelin (p-endothelin). Hypothesis: Central 24-h BP monitoring provides another measure of daily fluctuations in blood pressure than peripheral 24-h BP monitoring, because this measurement is painless and does not interfere with activities in the daytime or night-time sleep. In hypertension, chronic kidney disease and OSA the decease in nocturnal BP is lower than i healthy subjects. In OSA the decrease in the nocturnal BP is inversely correlated with the severity of OSA. In OSA is the renal tubular absorption of water and sodium abnormal with increased tubular absorption of water with AQP2 and of sodium by ENAC. In OSA, there is increased activity of the renin-angiotensin-aldosterone system, increased endothelin in plasma and increased vasopressin in plasma.