Abstract
The ventral prostate of the rat both after in vitro incubation and in vivo experiments was found to contain appreciable 5α-reductase activity, whilst a very low activity was registered in the diaphragm and liver. Neither Estracyt® nor LEO275 (Estracyt® without the phosphate group in position 17 of the oestradiol moiety) had an inhibitory effect on the enzyme activity after in vitro incubation but equivalent amounts of oestradiol-17β and oestradiol-17β-phosphate significantly reduced 5α-reductase activity. When Estracyt® was injected in vivo no influence on activity was registered in "short term" experiments while a significant inhibition was found after "long term" treatment in vivo. Possible explanations for this "long term" effect of Estracyt® on 5α-reductase activity are discussed.