Endocrine Abstracts

The effect of Oestrogen on brain aging. Declan GM Murphy.
The biological basis of human brain aging is poorly understood and there are few proven treatments for age-related brain disease. Recently, however, it has been suggested that HRT may have a 'neuroprotective' effect. Some studies report no beneficial effect of HRT on cognitive function in healthy older women though most show a significant benefit to memory and/or a general cognitive enhancement. There is perhaps greatest evidence for a positive effect on verbal memory. Moreover, HRT may reduce the risk and delay the onset of developing Alzheimer's disease (AD). However, recent randomized trials suggest no beneficial effect of long term oral HRT on cognitive function in women who already have a diagnosis of AD Although one study (using oestradiol patches) reported a significant benefit. Thus there is significant evidence that HRT improves cognitive function in postmenopausal women, and reduces a womans' risk for developing AD but there is less evidence that HRT is an effective treatment for established AD. The mechanisms by which HRT exerts these effects are unknown, and are most likely multimodal. One explanation for the beneficial effect of HRT on brain may be that it reduces age-related differences in brain systems which are crucial to higher cognitive function, and which are also implicated in AD and aging (e.g. the cholinergic system)
I will present recent work from our laboratory investigating the effect of oestrogen on brain aging. Also, I will present evidence that the action of oestrogen occurs in the same brain regions which are affected by gene products coded for by X chromosome CGG triplet repeats.