Estradiol upregulates Bcl-2 expression in adult brain neurons.
Bcl-2, a protein which negatively modulates apoptosis, is up-regulated by estrogen in several tissues. To determine the effect of estradiol on Bcl-2 in the adult brain, its immunoreactive distribution was examined in the hypothalamic arcuate nucleus of female rats under different endocrine conditions. The number of Bcl-2-immunoreactive neurons was significantly increased (p < 0.001) on the day of estrus compared with proestrus, diestrus and metestrus, was decreased by ovariectomy and showed a dose-response increase after estradiol administration to ovariectomized rats. Progesterone, when injected simultaneously with estradiol, reduced the effect of estradiol. These findings indicate that ovarian hormones regulate Bcl-2 in hypothalamic neurons and suggest that this protein may be involved in the neuroprotective effects of estrogen.
Garcia-Segura
L M
LM
Instituto Cajal, CSIC, Madrid, Spain.
Cardona-Gomez
P
P
Naftolin
F
F
Chowen
J A
JA
D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism; D001921:Brain / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D002552:Cerebral Ventricles / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology*; D004971:Estrus; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D010052:Ovariectomy; D011374:Progesterone / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar
D019253:Proto-Oncogene Proteins c-bcl-2; D011374:Progesterone; D004958:Estradiol