EVIDENCE FOR THE COMMON IDENTITY OF RABBIT OVARIAN 20α- AND 17β-HYDROXYSTEROID DEHYDROGENASES

Abstract

Department of Reproductive Biology, Case Western Reserve University, Cleveland, Ohio 44106, U.S.A. (Received 21 April 1978) In recent years, there has been disagreement over the possibility that the activities of the 20α- and 17β-hydroxysteroid dehydrogenases in various endocrine tissues may depend on the same enzymic protein. Contradictory results have been obtained with human placental tissue. The results of Purdy, Halla & Little (1964) and Jarabak & Sack (1969) suggest that the two activities are dependent on the same protein, whereas the data of Karavolas & Engel (1971) suggest that they are not. This paper reports our findings on the problem using rabbit ovarian tissue. Ovaries containing corpora lutea at random stages of development or regression were obtained from rabbits undergoing ovariectomy in a separate experiment. The complete ovaries were homogenized in 12 ml 0·25 m-sucrose and centrifuged for 30 min at 105 000 g. The supernatant fractions were used for