Prenatal exposure to estrogen and sexual orientation in women
Studies of women exposed to high levels of estrogens prenatally could provide information regarding effects of early exposure to masculinizing hormones on sexual differentiation of brain and behavior independent of influences on the external genitalia.
1984 Study Abstract
Pre- and postnatal influence of testosterone propionate and diethylstilbestrol on differentiation of the sexually dimorphic nucleus of the preoptic area in male and female rats, US National Library of Medicine National Institutes of Health, Brain research, NCBI PubMed PMID: 6733514, 1984 Jun.
Image credit Caroline.
The volume of the sexually dimorphic nucleus in the preoptic area (SDN-POA) of the rat brain is several fold larger in males than in females.
- When female rats were treated pre- and postnatally with testosterone propionate (TP) or with diethylstilbestrol (DES) they became anovulatory and their SDN-POA developed equivalent in size to that of normal males.
- Identical treatment of male rats resulted in deficient testicular development, but had no influence on SDN-POA volume.
The results indicate that the gross morphological sex difference in SDN-POA volume can exclusively be controlled by the hormonal environment during the critical period of sexual brain differentiation, and that non-steroidal estrogens are just as effective as convertible androgens in stimulating SDN-POA differentiation.