OBJECTIVES: A) My principal objective is to determine the basis of deranged albumin homeostasis in rats with either renal failure or experimental nephrosis. I will measure the rate of albumin synthesis in vivo in nephrotic rats to elucidate the influence of dietary protein and of serum oncotic pressure on the rate of albumin synthesis during the establishment of the nephrotic syndrome. I will determine the precise abnormalities in albumin homeostasis in experimental nephrosis. I have determined that uremia poses no additional constraints on the synthesis and distribution of albumin. Patients appear to respond to peritoneal losses of albumin by increasing albumin synthesis to a much greater degree than do nephrotic patients. I plan to study albumin synthesis in rats in which albumin is removed by peritoneal lavage and compare them to both nephrotic animals and animals acutely plasmaphoresed.