Oral homeostasis strongly influences taste perceptions. It depends on a healthy oral epithelium and salivary gland secretions, which are both regulated by sex hormones. The aim of this thesis was to identify the effect of an oral exposure to Bisphenol A, a food packaging and dental sealer component, and of a soy-diet containing phytoestrogens on oral homeostasisTwo experiments were conducted in adult rats: a dose-response study of BPA (5μg 12.5 mg / kj / day), and a study about the impact of a soy-diet on the BPA disrupting effects. By using gustation choice tests, and histological and qPCR-TR molecular approach, we identify for the first time an action of BPA on dry mouth. We found that BPA reduced water consumption (p <0.01), increased salt intake (p <0.05) and decreased sugar intake (p <0.05), and also modulated salivary secretions. These effects were partially reversed by stopping oral exposure. In contrast, the soy-diet increased water intake (p <10-6) and decreased in salt preference (p <0.05) by comparing to the semi-synthetic diet did, and may correct the effects of BPA.These studies show that BPA and phytoestrogens exert agonist or antagonist estrogenic effects depending on the biological target, and that a soy-based diet can erase most of the observed BPA effects
