THE SITE OF PRODUCTION OF OESTROGENIC HORMONES IN HUMAN PREGNANCY. II.

Abstract

Spayed female mice were injected with human fetal adrenal and placental tissue from fetuses delivered by hysterotomy in cases of legal abortions. Vaginal smears were inspected daily for signs of estrogenic activity. Estrous smears were never encountered when either adrenal or placental tissue was injected, but when both tissues were injected together, the mice most often went into estrus. From these results it is assumed that the estrogens of human pregnancy are produced neither by the placenta nor by the fetal adrenal alone, but by a complex procedure involving both tissues. It is thought most likely that the fetal adrenals produce a steroid precursor which is metabolized into estrogens by the placenta and excreted as such in the urine of the mother.