Protection of cortical cells by equine estrogens against glutamate-induced excitotoxicity is mediated through a calcium independent mechanism.

Background: High concentrations of glutamate can accumulate in the brain and may be involved in the pathogenesis of neurodegenerative disorders such as Alzheimer's disease. This form of neurotoxicity involves changes in the regulation of cellular calcium (Ca2+) and generation of free radicals such as peroxynitrite (ONOO-). Estrogen may protect against glutamate-induced cell death by reducing the excitotoxic Ca2+ influx associated with glutamate excitotoxicity.

Potential role of the interaction between equine estrogens, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) in the prevention of coronary heart and neurodegenerative diseases in postmenopausal women.

Background: An inverse relationship between the level of high-density lipoprotein (HDL) and coronary heart disease (CHD) has been reported. In contrast, oxidized HDL (oHDL) has been shown to induce neuronal death and may play an important role in the pathogenesis of CHD. In the present study we have investigated a: the effect of various equine estrogens on HDL oxidation, b: the inhibition of LDL oxidation by HDL and c: the effect of these estrogens on LDL oxidation in the presence of HDL.