Renal hemodynamic effects of aliskiren in comparison to ramipril.

1. Male caucasian patients;

2. Age >18 and <70 years;

3. Overweight or obese (BMI >27 and <35 kg/m2);

4. Essential hypertension according to WHO-criteria (systolic and diastolic bloodpressure >140 or <90 mmHg, respectively);

5. Normal renal function (creatinine clearance >90 ml/min/1.73m2);

6. Normo- or microalbuminuria (albuminuria <300mg/day);

7. Written informed consent.

1. Inability to meet inclusion criteria;

2. Previously treated (within 3 months prior to start of study) with aliskiren or ramipril;

3. Cardiovascular disease (myocardial infarction, angina pectoris, percutanous transluminal coronary angioplasty, coronary artery bypass grafting, stroke, heart failure (NYHA I-IV), Diabetes Mellitus;

4. Active malignancy;

5. Any medication, surgical or medical condition which might significantly alter the absorption, distribution, metabolism, or excretion of medications including, but not limited to any of the following:

A. History of active inflammatory bowel disease within the last six months;

B. Major gastrointestinal tract surgery such as gastrectomy, gastroenterostomy, or bowel resection;

C. Gastro-intestinal ulcers and/or gastrointestinal or rectal bleeding within last six months;

D. Pancreatic injury or pancreatitis within the last six months;

E. Evidence of hepatic disease as determined by any one of the following: ALT or AST values exceeding 3x ULN at inclusion, a history of hepatic encephalopathy, a history of esophageal varices, or a history of portocaval shunt;

F. Evidence of urinary obstruction of difficulty in voiding at inclusion.

6. History of severe hypersensitivity or contraindications to ramipril or aliskiren;

7. Hypersensitivity to 125I-iothalamate or 131I-hippuran;

8. History of angioedema;

9. History of autonomic dysfunction (e.g. history of fainting or clinically significant orthostatic hypotension);

10. Participation in any clinical investigation within 3 months prior to start of the study;

11. Donation or loss of 400 ml or more of blood within 3 months prior to initial dosing;

12. History of drug or alcohol abuse within the 12 months prior to dosing, or evidence of such abuse as indicated by the laboratory assays conducted during the screening;

13. History of noncompliance to medical regimens or unwillingness to comply with the study protocol;

14. Any surgical or medical condition, which in the opinion of the investigator, may place the patient at higher risk from his/her participation in the study, or is likely to prevent the patient from complying with the requirements of the study or completing the study.