The proposed research project aims at studying four different types of 15-hydroxyprostaglandin dehydrogenases and two types of ketoprostaglandin reductases. The 15-hydroxyprostaglandin dehydrogenases control the biological inactivation of prostaglandins, whereas the 9-prostaglandin reductase regulates the interconversion of functionally different prostaglandins and the 15-ketoprostaglandin reductase catalyzes the reactivation of some inactive prostaglandin catabolites. Following aspects of research on these enzymes will be investigated. (1) purification and characterization (2) regulatory properties (3) antibody production (4) development of radioimmunoassay (5) possible roles in genetic hypertension. The results of this research program will provide us some fundamental understanding of the structure and function of renal enzyme systems as well as possible involvement of the enzyme systems in genetic hypertension. Moreover, it will also give valuable information to the similar studies in various tissues and further stimulate investigations on the roles of prostaglandins in various physiological systems.