title: Estrogen and apoptosis in the developing sexually dimorphic preoptic area in female rats.
abstract: Effect of estrogen on apoptotic cell death was studied in the two sexually dimorphic neuronal groups in the developing rat preoptic area (POA): the anteroventral periventricular nucleus of the POA (AVPvN-POA); and the sexually dimorphic nucleus of the POA (SDN-POA). A specific labelling of nuclear fragmentation was performed by terminal deoxynucleotydyl transferase(TdT)-mediated dUTP-biotin nick end-labeling method (TUNEL method) to demonstrate apoptosis. In the AVPvN-POA whose size is larger in females than in males, the number of TUNEL-positive cells was not significantly different between day 5 control and female pups sacrificed 10 h after 25 micrograms estradiol benzoate (EB) injection. However, TUNEL-positive cells showed a significant increase in the female pups sacrificed 24 h after EB injection, compared to that shown in the control female pups. In the SDN-POA whose size is larger in males than in females, EB injection significantly decreased TUNEL-positive cells in the female pups sacrificed 24 h after EB injection, compared to that in controls. These results suggest that estrogen regulates the neuronal number by facilitating apoptotic cell death in the developing AVPvN-POA or by inhibiting it in the developing SDN-POA.
authors.affiliation: Department of Anatomy, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Arai
authors.forename: Y
authors.initials: Y
authors.lastname: Sekine
authors.forename: S
authors.initials: S
authors.lastname: Murakami
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development; D017209:Apoptosis / Q000187:drug effects*; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D011301:Preoptic Area / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D012733:Sex Differentiation / Q000502:physiology*
chemical_list: D004967:Estrogens