Age-related changes in hippocampal estrogen receptor alpha in female mice

MORENO PIOVANO G; ROSSETTI MF; DUDIUK C; VARAYOUD J; MUÑOZ-DE-TORO M; LUQUE EH; RAMOS JG

Congreso; II Reunión Conjunta de Neurociencias.; 2010

A good amount of evidence indicates that estrogens modulate hippocampal activity, an area of brain related to cognition and memory. The biological effects of estrogens are mainly mediated by estrogen receptors (ERs) which in turn are regulated by several factors including age, sex and gonadal steroid hormones. While the molecular actions of steroid hormones on the hippocampal formation have been studied, considerably less is known about the molecular mechanisms that regulate the expression of ERs. In the present study, to reveal the effects of normal aging on ERa expression in the hippocampus, we examined ERa expression using young (4 month, control group) and adult (11 months) intact CF-1 female mice. By microsurgery complete hippocampus were extracted, which were individually processed. The expression of ERa mRNA and relative transcriptional activity of promoters A, C and F were evaluated by real time RT- PCR. Adult  mice  showed  a  significant  decrease  in  the expression  of  ERa total mRNA  when  compared  with  young controls  (p <0.05). In considering the relative activity of each of the ERa gene promoters, a significant decrease was observed in the activity of promoters A and C (p <0.001) in adult animals, while F promoter relative activity remained unchanged (p = 0.99). These results demonstrate that aging is associated with a decrease in the expression of ERa in the hippocampus. This down-regulation would be mediated, at least in part, by a decreased activity of promoters A and C.