1. Department of Medicine, Roger Williams General Hospital, and the Section of Biochemical Pharmacology, Division of Biological and Medical Sciences, Brown University, Providence, R.I. 02912.
2. Brown University, Providence, R.I. 02912.
3. Section of Biochemical Pharmacology, Brown University, Providence, R. I. 02912.
4. Roger Williams General Hospital, Providence, R. I. 02908.