Estrogen Receptor Activation May Prevent Adiposity, Insulin Resistance
HealthDay News — Selective activation of estrogen receptor α (ERα) activation function-1 (AF1) prevents obesity, steatosis, and insulin resistance in a mouse model, according to an experimental study published online May 11 in The American Journal of Pathology.
Maeva Guillaume, MD, PhD, from the Université de Toulouse in France, and colleagues fed ERα-deficient, or ERα-AF1-deficient ovariectomized female mice a high-fat diet and concomitantly administered vehicle or tamoxifen, which acts as a ERα-AF1 agonist/ERα-AF2 antagonist.
The researchers found that tamoxifen significantly reduced food intake and totally prevented adiposity, insulin resistance, and steatosis in ovariectomized wild-type mice. In ERα-deficient and ERα-AF1 deficient mice these effects were abolished. In ERα-AF1-deficient mice, hepatic gene changes that were elicited by tamoxifen in wild-type mice were abrogated.
"The combination of pharmacologic and transgenic approaches thus indicates that selective ERα-AF1 activation by tamoxifen is sufficient to elicit metabolic protection, contrasting with the specific requirement of ERα-AF2 in the metabolic actions of 17β-estradiol," the authors write. "This redundancy in the ability of the two ERα-AFs to separately mediate metabolic prevention strikingly contrasts with the contribution of both ERα-AFs in breast cancer proliferation, shedding new light on the therapeutic potential of selective ER modulation."