title: Perinatal exposure to estradiol masculinizes aspects of sexually dimorphic behavior and morphology in gray short-tailed opossums (Monodelphis domestica).
abstract: The effects on adult sexually dimorphic behavior of perinatal exposure to estrogen were examined by treating male and female gray opossums with estradiol (EST), an estrogen receptor antagonist (tamoxifen:TX) or oil control (OIL) during the first week of life, a time period corresponding in this marsupial to late gestation in rodent species. Following gonadectomy and replacement therapy with testosterone in adulthood, males showed more scent-marking behavior than females and EST animals showed more scent marking than TX or OIL animals. Also, phalluses were longer and body weight was higher in males than in females and in EST-treated animals than in TX-treated animals; OIL animals were intermediate in these morphological measures. EST animals of both sexes showed less female-typical screeching threat behavior than OIL or TX animals. Because these hormone manipulations were conducted on the "fetus" directly in this marsupial (rather than via the maternal circulation as in previously studied eutherian species), these findings provide unique confirming evidence for masculinization of aspects of behavior and morphology by early exposure to estradiol in mammals.
authors.affiliation: Department of Psychiatry, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, New Jersey 07103, USA.
authors.forename: B H
authors.initials: BH
authors.lastname: Fadem
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology; D001522:Behavior, Animal / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D004343:Drug Implants; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology*; D004965:Estrogen Antagonists / Q000494:pharmacology; D005260:Female; D008297:Male; D009893:Opossums / Q000502:physiology*; D010413:Penis / Q000187:drug effects / Q000254:growth & development; D012543:Scent Glands / Q000187:drug effects / Q000254:growth & development; D012727:Sex Characteristics; D013629:Tamoxifen / Q000494:pharmacology; D013737:Testis / Q000187:drug effects / Q000254:growth & development; D013739:Testosterone / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D004343:Drug Implants; D004965:Estrogen Antagonists; D013629:Tamoxifen; D013739:Testosterone; D004958:Estradiol