This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This project is composed of two studies. Study 1 consists of 9 to 13 maintenance hemodialysis (MHD) patients who are clinically stable and will undergo nitrogen balance studies while they ingest, for 17 days each, diet protein intakes providing 0.60, 0.80, 1.00, 1.15 and 1.30 g protein/kg/day. 13 C-leucine turnover studies 13C-urea kinetic studies and measurements of plasma amino acides, dialysate amino acids, peptides and proteins, muscle biopsies for measurement of protein and gene expression for IGF-I, IGF-II, IGF-receptor, myostatin, and IGF-binding proteins and body composition anthropometry and dual x-ray pohton absorptiometry DXA will be measured. In Study 2, 70-80 MHD outpatients will be randomly assigned to a DPI of 1.00 or 1.30 g/kg/day for five months each. Total body protein will be assessed by measurements of total body nitrogen and total body potassium. Other components of body composition will be assessed using anthropometry, DXA, BIA and near infrared interactance.