Dr. Benyajati plans to study the mechanisms for the reabsorption of taurine, and aminosulfonic acid, by primative vertebrate kidneys. Taurine biosynthesis in vertebrates is extremely slow so most of the taurine that concentrates in brain and heart tissue is of dietary origin. Dietary taurine has been shown to be essential for the maintenance of normal cardiac rhythms in mammals and birds and is thought to be important in the maintenance of normal membrane potentials in the nerve cells of the brain and central nervous system. In sharks, taurine is used to regulate intracellular osmotic pressure rather than maintain membrane functions. Both shark and rat kidneys have special beta-amino acid transport systems for recovering and maintaining adequate blood levels of this important compound. Dr. Benyajati will employ several techniques to achieve an understanding of taurine transport and reabsorption by reptilian kidneys. Studies with these kidneys are important because of the intermediate position in terms of the evolution of birds and mammals from lower vertebrates. These studies include the microperfusion of isolated kidney tubles to judge uptake in simulated flow-through studies with intact kidneys to measure the in vivo performance under various physiological conditions. The results will give important information on the regulation of the membrane transport of this interesting group of important amino acids.
