Chronic treatment of female transgenic HER-2/neu mice with metformin slightly decreases food consumption but fails to reduce body weight or temperature, slows down age-related rise in blood glucose and triglycerides level, as well as the age-related switch-off of estrous function, prolongs mean lifespan by 8% (p < 0.05), the mean lifespan of last 10% survivors by 13.1% and maximum lifespan by 1 month. Metformin treatment significantly decreases incidence and size of mammary adenocarcinomas and increases the mean latency of the tumors .
Chronic treatment of female outbred SHR mice with metformin slightly modified food consumption but decreases the body weight after the age of 20 months, slows down the age-related switch-off of estrous function, increases mean lifespan by 37.8% mean lifespan of the last 10% survivor by 20.8%, and maximum lifespan by 2.8 month (+10.3%). Treatment with metformin fails to influence blood estradiol concentration and spontaneous tumor incidence in female SHR mice .
In female SHR mice, metformin increases lifespan lifespan and postpones tumors when started at young and middle but not at old age. Chronic treatment of female outbred SHR mice with metformin started at the age of 3, 9 or 15 months decreases body temperature and postpones age-related switch-off of estrous function. Treatment with metformin started at the age of 3 months increases mean lifespan by 14% and maximum lifespan by 1 month. Treatment started at the age of 9 months insignificantly increases lifespan by only 6%, whereas the treatment started at the age of 15 months fails to increase lifespan. The mean lifespan of tumor-free mice increases by 21% (started at 3 months), by 7% (started at 9 months) and in contrast is reduced by 13% (started at 15 months). If started at 3 and 9 months, metformin delays the first tumors by 22% and 25%, correspondingly .
Transgenic FVB/N female mice carrying HER-2/neu mammary cancer gene receiving metformin with drinking water 5 days a week starting from the age of 2 months exhibit a slight reduced food consumption without change in water consumption and dynamics of weight gain. Their mean lifespan increases by 8% in 10% of the long-lived mice it is prolonged y 13.1% and the maximum lifespan is prolonged by 1 month. The total incidence of mammary adenocarcinoma and their multiplicity does not change under the effect of metformin, while the latency of tumor development increases and the mean diameter of tumors decreases .
Chronic treatment of inbred 129/Sv mice with metformin slightly modifies food consumption but fails to influence the dynamics of body weight, decreases by 13.4% the mean lifespan of make mice and slightly increases the mean lifespan of female mice (by 4.4%). Metformin treatment fails to influence tumor incidence in male 129/Sv mice, decreases by 3.5 times the incidence of malignant neoplasms in female mice while somehowwhat stimulate formation of benign vascualr tumors in the latter .