Ovariectomy leads to increased insulin resistance in human apolipoprotein B transgenic mice lacking brown adipose tissue.

We studied the role of estrogen in the gender differences in insulin resistance observed in the apoB/BATless mouse, a model of obesity, insulin resistance, and hyperlipidemia. Ovariectomized apoB/BATless mice were more obese and more insulin-resistant than sham ovariectomized apoB/BATless mice. Estrogen replacement by subcutaneous pellet reversed the obesity, lowered plasma insulin levels, and normalized both glucose tolerance and insulin sensitivity associated with ovariectomy. The apoB/BATless mouse should be a good model to delineate the molecular mechanisms whereby estrogen protects against insulin resistance.