RESUMEN
AIMS: To investigate the 17-ß estradiol in the acetylcholinesterase activity and lipid peroxidation in the brain and blood of ovariectomized rats of different ages. MAIN METHODS: Animals were randomly assigned into three experimental groups of each age (n=6). Control groups consisted of adult (sham-A) and middle-aged (sham-MA) female rats, ovariectomized adult (OVX-A) and middle-aged (OVX-MA) rats without estrogen therapy reposition, and ovariectomized adult (OVX+E2-A) and middle-aged (OVX+E2-MA) rats treated with 17-ß estradiol for 30days. After this period, AChE activity and lipid peroxidation were measured in the brain and blood. KEY FINDINGS: The AChE activity increased (p<0.05) in striatum (ST) in OVX-A, OVX+E2-A and OVX-MA, and hippocampus (HP) in OVX-MA. The enzyme activity decreased (p<0.05) in ST of OVX+E2-MA, and cerebral cortex (CC) in OVX+E2-A, OVX-MA and OVX+E2-MA. Blood AChE activity increased (p<0.05) in OVX+E2-A and decreased (p<0.05) in OVX-MA. Lymphocyte AChE activity increased (p<0.05) in OVX-A and OVX+E2-A and decreased (p<0.05) in OVX-MA. Lipid peroxidation increased (p<0.05) in ST of OVX-A, CC of OVX-A and OVX-MA, HP of OVX-A, and cerebellum (CE) of OVX-A, OVX-MA, and OVX+E2-MA. Lipid peroxidation decreased (p<0.05) in ST, CC and CE of OVX+E2-A, and ST and HP of OVX+E2-MA. Similar values of lipid peroxidation to control groups were found in ST and HP of OVX-MA, HP of OVX+E2-A and CC of OVX+E2-MA. SIGNIFICANCE: 17-ß estradiol is able to modulate the AChE activity and non-neuronal cholinergic response as well as to reduce lipid peroxidation. Its response is dependent on the age and brain structure analyzed.