The CRC is designed to serve as a facility for patient-based fundamental and applied research. The following studies are among those presently planned for facility: The Effect of Betaine on Cognitive Function, Behavior, Platelets and Amino Acid Patterns in Homocystinuria. Determination of Renal Iodide Clearance as a Function of Chloride Clearance in the Salt Deplete and the Salt Replete State. Use of the Fractional Excretion of Lithium to Study Basal and Salt-loaded Electrolyte Handling by the Kidneys of Hypertensive and Normotensive Patients. Use of the Biologic Decay of Na22 for Estimation of Human Sodium Intake. Determination of Net Mineralocorticoid Activity in Pregnant Patients by Determining Rectal Potential Differences. Determination of the Effect of Insulin on Sodium Excretion in Obese and Non-obese Individuals. Study of the Mechanism of Edema in Idiopathic Edema, and Determining the Effects of Therapy. Effect of Insulin on Fractional Sodium Excretion in the Insulin-Resistant Obese.