Inorganic phosphate is an important part of cells as well as body components such as bone. The amount of phosphate within an organism can alter bodily calcium balance, acidity of body fluids, and growth. Phosphate regulation is therefore important in all vertebrates. Dietary intake, intestinal absorption and renal excretion determine the body phosphate balance. The processes in the kidneys which control the excretion of phosphate are not understood in animals such as birds and fishes. Unlike mammals, the latter have a mechanism to transfer phosphate directly from blood to the urine through kidney cells. The objectives of this work include the study of the mechanism of phosphate transfer at both the cellular and cell membrane levels. Regulation of phosphate excretion by the kidneys involves the interaction of hormones, acid-base balance, and dietary phosphate availability. Dr. Renfro will examine the basic cellular processes by which these factors alter body phosphate.
