Chronic Kidney Disease in Relation to Alterations in Protein and Amino Acid Metabolism and Function

This study involves one test day of approximately 7-8 hours. On this test day subjects will ingest a sugar drink to assess gut permeability and gut function, and a protein meal to measure digestion/absorption and the anabolic response to food intake. Subjects will also receive a mixture of amino acids that are made a little heavier than normal, called stable isotopes. This stable isotopes is used to investigate protein behavior in the body (protein kinetics). Blood (100-120 ml in total) and urine samples will be collected over 7.5 hours.