The Effects of Isotonic and Hypertonic Saline Infusion on Renal Biomarkers in Healthy Young Subjects

25 healthy subjects from age 18-45 are recruited.

Subjects will be examined on three examination days. Four days prior to the examination days the subjects will consume a standard diet based on the amount of sodium and calories.

On the examination day subjects are randomised to an infusion with either isotonic saline 23 ml/kg, hypertonic saline 7 ml/kg or glucose 23 ml/kg for a period of 50 minutes.

Renal function is measured by renal clearance of 51Cr-EDTA, urinary sodium, potassium and creatinine.

Urinary NCC, NKCC and ENAC will be measured to evaluate the activity of sodium channels in the nephron.

Inclusion criteria

• healthy males and females
• age 18-45
• BMI range 18,5-30,0 kg/m2

Exclusion criteria

• hypertension (ie ambulatory BP >130 mmHg systolic or/and >80 mmHg diastolic)
• history or clinical significant signs of heart, lung, liver, kidney, endocrine, brain or neoplastic disease.
• alcohol abuse
• drug abuse
• smoking
• pregnancy or nursing
• blood donation within a month prior to examination
• Medical treatment apart from oral contraception