Aging effects in energy balance in all tissues and organs, including the cardiovascular. The risk of cardiovascular disease is drastically higher in postmenopausal women than in premenopausal women. Estrogen plays an important role in the cardiac function and body’s metabolism. The aim of this study was to determine whether 17β-estradiol (E2) has beneficial effects on insulin resistance and some key stages of the insulin signalling pathway in the aged hearts. Young and aged female Wistar rats were ovariectomized and were randomly divided into three groups: young (YS) and aged (AS) sham, young (YV) and aged (AV) vehicle, and young (YE2) and aged (AE2) E2 treatment groups. E2 (1 mg/kg) was administrated every four days for four weeks. Results showed that ovariectomy increased fasting blood glucose, insulin, and HOMAIR in young, while none of these parameters was affected in aged animals. On the other hand, aging itself increased these variables. Furthermore, E2 therapy alleviated these changes in both young and aged animals. Moreover, aging also decreased the p-IRS1, p-Akt level, and translocation of GLUT4 to the plasma membrane. E2 reduced the negative impact of menopause and aging on insulin sensitivity by favoring increase in the level of IL-10 and decrease in the levels of TNF-α and IL-1β. Our results indicated that the heart response to E2 depended on age, and E2 increased insulin sensitivity in the heart of both young and aged animals by altering inflammatory conditions. Determining the exact mechanism of this action is suggested in future studies.
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