1. Hypertension Research Laboratory, Veterans Administration Hospital and Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106, U.S.A.
2. Papanicolaou Cancer Research Institute and Department of Medicine, University of Miami School of Medicine, Miami, Fla. 33152, U.S.A.
3. Department of Biochemistry, University of Colorado School of Medicine, Denver, Colo. 80220, U.S.A.