Estradiol valerate and tibolone: Effects on memory

17-β estradiol in the acetylcholinesterase activity and lipid peroxidation in the brain and blood of ovariectomized adult and middle-aged rats

“…Estrogen replacement therapy has showed a reduction in risk factors related to aging, oxidative stress (Moorthy et al, 2005;Aguiar et al, 2006Aguiar et al, , 2008, and neurological disorders (Wise et al, 2001;Pozzi et al, 2006;Vegeto et al, 2008). Thus, we hypothesized that 17-β estradiol replacement could improve parameters related to the AChE activity in the brain, total blood and lymphocytes, as well as lipid peroxidation in the brain and weight gain in adult and middle-aged ovariectomized female rats.…”

“…Although hormonal replacement therapy may be one of the greatest conquests in the battle for quality of life for women, many factors should be considered regarding its use (Aguiar et al, 2006). Estrogen replacement therapy has showed a reduction in risk factors related to aging, oxidative stress (Moorthy et al, 2005;Aguiar et al, 2006Aguiar et al, , 2008, and neurological disorders (Wise et al, 2001;Pozzi et al, 2006;Vegeto et al, 2008).…”

Effect of chronic administration of estradiol, progesterone, and tibolone on the expression and phosphorylation of glycogen synthase kinase‐3β and the microtubule‐associated protein tau in the hippocampus and cerebellum of female rat

“…Long‐term ovariectomy and menopause result in behavioral, neurochemical, and molecular deficits, which are partially normalized by hormone replacement therapy (HRT; Sherwin,2003; Chakraborty and Gore,2004). In this regard, TIB improved memory in a step‐down inhibitory task of ovariectomized young, adult, and old rats (De Aguiar et al,2006), and, even more importantly, it perhaps can preserve cognitive function and be able to prevent the cognitive deterioration in postmenopausal women in the short term (Pan et al,2003) and in long‐term treatments (Fluck et al,2002). Other studies have reported that TIB improves semantic and episodic memory in postmenopausal women that were treated with 2.5 mg/day (Albertazzi et al,2000; Fluck et al,2002).…”

“…Another group of rats received the TIB vehicle (water) by the same administration method. We decided to apply the 60‐day treatment because, in previous studies, it has been reported that TIB exerts effects on cognitive processes from the first 2 months of treatment at the same dose (De Aguiar et al,2006; Wu et al,2008). The animals were sacrificed by decapitation 24 hr after the end of treatments.…”

“…In hypothalamic neurons of the guinea pig, TIB administration rapidly attenuates the GABA B response (Qiu et al,2008). In the cortex and hippocampus of young, adult, and old ovariectomized rats, TIB decreases lipid hydroperoxidate levels, produces greater total antioxidant capacity (De Aguiar et al,2008), and improves memory in a step‐down inhibitory avoidance task (De Aguiar et al,2006). However, the effect of TIB on the expression and phosphorylation of tau protein is unknown.…”