Renal tubular sodium handling and plasma atrial natriuretic peptide, renin activity and aldosterone in untreated men under normal living conditions.

The associations between renal tubular sodium handling and plasma levels of atrial natriuretic peptide, renin activity and aldosterone were studied in 295 untreated men under normal living conditions. The renal clearance of ingested lithium was used as a marker of proximal tubular sodium handling. Plasma atrial natriuretic peptide was inversely related to creatinine clearance (r = -0.

Erythrocyte volume and blood pressure in a cross-sectional population-based study.

A reduction in mean erythrocyte volume has been reported in some strains of genetically hypertensive rat, and more recently it has been suggested that a similar alteration might be found in human essential hypertension. The relationship between erythrocyte volume and blood pressure was therefore studied in a random sample of an untreated male working population (n = 317; age 45.1 +/- 6.

Insulin-induced increase in heart rate and its prevention by propranolol.

Acute hyperinsulinaemia in the absence of changes in blood glucose increases heart rate in man. Animal studies have suggested that beta-adrenergic blockade does not prevent the insulin-induced increase in heart rate. The aim of the present study was to investigate the acute effect of insulin on heart rate and blood pressure in non diabetic subjects and, in particular, to determine whether beta-adrenergic receptor blockade would significantly influence the effect.

Erythrocyte sodium/lithium countertransport and renal lithium clearance in a random sample of untreated middle-aged men.

1. It has been proposed that the enhanced erythrocyte Na+/Li+ countertransport observed in many patients with essential hypertension could be a marker of abnormal renal proximal tubular function. We thus investigated the relationship of blood pressure and Na+/Li+ countertransport to an index of proximal tubular function such as renal Li+ clearance.

Calcium-channel blockers and sodium intake: a controlled study in patients with essential hypertension.

Thirteen patients with mild to moderate essential hypertension and whose average supine blood pressure with no treatment was 165/104 mmHg were studied as inpatients for 3 consecutive one-week periods on different sodium intakes. On the last day of each dietary period, they received a single, 20-mg nitrendipine tablet and blood pressure was monitored every 10 minutes for 2 hours after drug administration. Nitrendipine significantly lowered blood pressure independently of the level of sodium intake, and the maximum blood-pressure lowering effect was achieved approximately 1 hour after the dose.