IN VITRO ESTROGEN BIOSYNTHESIS FROM TESTOSTERONE BY HOMOGENATES OF PLACENTAS FROM NORMAL PREGNANCIES AND PREGNANCIES COMPLICATED BY INTRAUTERINE FETAL MALNUTRITION AND DIABETES

The aromatizing capacity of human placentas from normal and abnormal pregnancies was compared. Placental homogenates were incubated in vitro with 4-C14-testosterone and the extent of biosynthesis of radioactive estrone (the predominant estrogen formed) was determined. Nine out of 11 premature placentas showed values for conversion of testosterone to estrone which were in the lower range of those observed for placentas from normal term pregnancies; this lower activity was shown to be related to a lesser protein concentration in homogenates of premature tissue. Values for estrone formation from testosterone by homogenates of placentas from diabetic pregnancies were also in the lower range of those observed for normal term samples. In contrast, the aromatizing capacity of the placentas from cases of intrauterine fetal malnutrition was significantly greater than that of the normal term samples. This greater activity may reflect a compensatory mechanism for the decreased placental size which is characteristic of the more severs cases of fetal malnutrition. © 1969.