THE ACTIVITY OF SYNTHETIC ISOESTRONES IN PYRIDINE NUCLEOTIDE TRANSHYDROGENATION1

Abstract

Synthetic isoestrones were examined for the capacity to mediate pyridine nulceotide transhydrogenation or to act as substrates for 17β hydroxy-steroid dehydrogenase. 8-isoestrone was active in both systems. The other isoestrones tested showed neither activity. Previous studies have indicated that certain steroids have the property of accelerating transhydrogenation from a catalytic amount of TPNH to DPN in the presence of placental homogenate (1, 2). The structural requirements for striking stimulation of this system are the presence of an aromatic ring A and a 17B hydroxyl or 17 keto group (3, 4). The existence of synthetic isomers of estrone (5) permitted study of other steric requirements.