Estrogen blocks inducible nitric oxide synthase accumulation in LPS-activated microglia cells

Estrogens are thought to play a protective role against neurodegeneration t hrough a variety of mechanisms including the activation of growth factors a nd neurotransmitter synthesis, the control of synaptic plasticity and funct ions, and the blockade of oxidative reactions. We here propose a novel mech anism to explain the neuroprotective effects of estradiol by showing that e strogens may antagonize nitric oxide synthase activity and reduce the accum ulation of nitrites and nitrates consequent to various inflammatory stimuli . The potential anti-inflammatory activity of estradiol is analyzed in vitro in cells in culture including primary cultures of microglia and in vivo in a well-known model of inflammation. (C) 2000 Elsevier Science Inc. All righ ts reserved.