Parenteral 17beta-estradiol decreases fasting blood glucose levels in non-obese mice with short-term ovariectomy

Aims: Long-term ovariectomy-induced metabolic changes such as insulin resistance and glucose intolerance might be caused directly by estrogen deficiency and may occur partly as secondary effects of obesity arising due to the orexigenic effects of estrogen deficiency. Long-term estrogen treatment prevented those by exerting anorexigenic and metabolic actions in ovariectomized mice. However, the effect of short-term estrogen treatment on glucose metabolism in mice with short-term ovariectomy, during which ovariectomy-induced obesity does not develop, is not yet clear. The aim of this study was to evaluate the effect of short-term parenteral 17beta-estradiol treatment on glucose metabolism and blood glucose levels in mice at 2 weeks after ovariectomy, a time period during which ovariectomy-induced obesity does not develop. Main methods: We examined the effect of three 17beta-estradiol injections on fasting blood glucose levels, insulin resistance, components of the insulin signaling pathway. AMPK activation, and the expression of genes related to glucose metabolism in liver, skeletal muscle, and white adipose tissues of non-obese C57BL/6N mice with short-term ovariectomy. Key findings: Three 17beta-estradiol injections decreased the fasting blood glucose levels, activated AMPK, and decreased the expression of gluconeogenic genes, phosphoenolpyruvate carboxykinase, glucose-6-phosphatase and peroxisome proliferator-activated receptor-gamma coactivator-1 alpha in the liver. But three 17beta-estradiol injections did not affect insulin sensitivity and the components of the insulin signaling pathway in the liver and skeletal muscle. Significance: Short-term parenteral 17beta-estradiol treatment decreases the fasting blood glucose levels not via insulin sensitivity of the skeletal muscle in non-obese mice with short-term ovariectomy. (C) 2010 Elsevier Inc. All rights reserved.