Is resveratrol an estrogen agonist in growing rats

Trans-3,4,5-trihydroxystilbene (resveratrol), a polyphenolic compound found in juice and wine from dark-skinned grape cultivars, was recently shown to bind to estrogen receptors in vitro, where it activated transcription of estrogen-responsive reporter genes. The purpose of this 6-day study in weanling rats was to determine the dose response (1, 4, 10, 40, and 100 μg/day) effects of orally administered resveratrol on estrogen target tissues. The solvent (10% ethanol) had no significant effect on any measurement or derived value. 17β-Estradiol treatment (100 μg/day) decreased the growth rate, final body weight, serum cholesterol, and radial bone growth (periosteal bone formation and mineral apposition rates) at the tibia-fibula synostosis. In the uterus, 17β-estradiol treatment increased wet weight, epithelial cell height, and steady state messenger RNA levels for insulin-like growth factor I. In contrast, resveratrol treatment had no significant effect on body weight, serum cholesterol, radial bone growth...