Concepedia

Abstract

ABSTRACT The effects of oral administration of synthetic progestins on the urinary oestrogen excretion were examined. 17α-ethynyl-19-nortestosterone (ENT) or 17α-ethynyl-estr-4-en-17β-ol (EEL) caused a significant rise of oestrogen output in urine. It appeared that the increased output of oestrogen was due to the conversion of ENT or EEL to ethynyl-oestradiol (EE2). Such a conversion of progestin was also observed with 17α-methyl-19-nortestosterone. To obtain the direct evidence for the conversion of ENT to EE2, human placental homogenates were incubated in vitro first with 19-nortestosterone. The approximate yield of oestrone was 20 percent of that observed with testosterone. However, a conversion of ENT to EE2 was not detected.