Adiponectin Regulation of Glucose Uptake and Growth in Mammary Epithelial Cells

초록

The objective of the research was to identify the presence of adiponectin receptors and to study adiponectin action on glucose uptake and growth in mouse mammary epithelial cells. These cells expressed adiponectin receptors, AdipoR1 and AdipoR2. Insulin (10 ng/ml) or insulin like growth factor-I (IGF-I, 10 ng/ml) alone did not alter the degree of AdipoR1 and AdipoR2 genes expression from 0 to 4 h incubation. Prolactin (10 ng/ml) or epidermal growth factor (EGF, 10 ng/ml) alone also did not induce the two genes’ mRNA in the incubation time. Adiponectin (1 μg/ml) alone or pre-incubation of insulin alone (100 ng/ml) for 2 h prior to adiponectin stimulation did not increase 2-deoxy-D-glucose,[1,2-3H] uptake but adiponectin+pre-incubation of insulin significantly increased glucose uptake compare to control (p<0.05). In a similar way, insulin alone or pre-incubation of adiponectin alone (2 h) did not increase glucose uptake but insulin+pre-incubation of adiponectin increased glucose uptake compare to control (p<0.05). Insulin sensitization for 2 h prior to adiponectin stimulation tended to increase glucose uptake response by the following adiponectin stimulation showing small interaction effect between insulin and adiponectin (p<0.1). However, adiponectin sensitization for 2 hours prior to insulin stimulation did not shown interaction effect between adiponectin and insulin (p>0.1). The glucose uptake by both of hormones seems to be not interactive but additive (p<0.05). Adiponectin in the presence of 2% FBS decreased DNA synthesis of mammary epithelia (p<0.05). AICAR (100 or 200 μM), AMPK activator, decreased mammary epithelial cell growth in the presence of 2% FBS. These results indicate that adiponectin pathway has inhibitory effect on mammary epithelial cell growth.

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