Arzoxifene (LY353381) hydrocloride is a selective estrogen receptor modulator that is a potent estrogen antagonist in mammary and uterine tissue while acting as an estrogen agonist to maintain bone density and lower serum cholesterol . In Vitro Arzoxifene inhibits cell growth as effectively as the antiestrogen tamoxifen. Northern analysis reveals that arzoxifene exerts a statistically significant inhibition of pS2 and progesterone receptor B mRNA expression. Significant agonistic effect is observed on the antitrypsin mRNA expression. In contrast to estradiol and tamoxifen, arzoxifene does not upregulate cathepsin D mRNA and protein expression. MCE has not independently confirmed the accuracy of these methods. They are for reference only. In Vivo Arzoxifene prevents the ovariectomy-induced increase in body weight and serum cholesterol levels of treated rats and lowers them to below sham levels in a dose dependent manner, with maximum efficacy similar to estrogen or raloxifene. Arzoxifene (LY353381.HCl) prevents loss of bone due to ovariectomy with an ED 50 of about 0.01 mg/kg with maximal efficacy observed at 0.1-1 mg/kg/day. Arzoxifene (LY353381.HCl) antagonizes the estrogen-induced elevation in uterine weight down to vehicle-dosed control levels with ED 50 of 0.03 mg/kg/day. MCE has not independently confirmed the accuracy of these methods. They are for reference only. Animal administration Rats Antiestrogen activity is evaluated in 21-day old Sprague Dawley rats.17α-Ethynyl estradiol at 0.1 mg/kg/day is used as the estrogenic stimulus to increase uterine weight in these rats. Arzoxifene HCl (LY353381.HCl)LY353381.HCl (0.001-10 mg/kg) or raloxifene (1 mg/kg) are administered by oral gavage in a volume of 0.2 mL, 15 min prior to the EE2 gavage. Dosing with test compounds is continued for 3 consecutive days. Animals are fasted over night, following the final dose . aladdin has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid IC50& Target:Estrogen receptor