Influence Of Estrogen On The Sweet Taste Preference Of Mice And The Related Modulations On The Peripheral Pathway

Humans can perceive sweet, sour, bitter, salty and umami five basic tastes,sweetness as one of the most important kind of tastes, indicates that the presence of thebody’s energy source-carbohydrates, Estrogen has been known to be associated withthe perception of sweetness, which can modify people’s intake of carbohydrates byaffecting the perception of sweetness and closely related to the occurrence of obesityand diabetes. However, the mechanism of how is the estrogen influence sweet tasteperception, still lack of reliable data. In this study, we have established the C57BL/6mouse model of estrogen deficiency, by the means of ovariectomy. The consequentmodifications of the estrogen in mice sweet taste perception threshold, feeding, weight,the number and maximum cross-sectional areashape of taste buds, and the expressionof related signal molecules at sweet taste transduction in the oral cavity and intestinalhave been analyzed on behavioral, molecular biology, morphology and othertechnology。We first established the mice model of estrogen deficiency by means ofovariectomy, through detecting the levels of estrogen, body weight and food intake tovalidate the model. Then we further use behavioral testing, qPCR and Western blot, totest the influence of estrogen in taste buds and the sweet taste transduction relatedsignal molecules in taste cells at different periods after ovariectomy (1w,2w,4w,6wand8w). The results showed that, with estrogen deficient mice, the estrogen levels inthe blood of the mice decreased significantly, and the body weight increased. TBP testsshowed that lack of estrogen in mice increased the prefernce threshold and decreasedpreference ratios at low concentrations for AK and sucrose solution. However, the prefernce threshold and preference ratios were returned to normal control group levelsthrough given the estrogen replacement therapy. Further investigation on the sweettaste transduction related molecules and protein expression in the tongue and softpalate were carried on, the results show that after ovariectomy, the expression of T1R3sweet receptors was decreased significantly in tongue, and those of key signalingmolecule Gα-gustducin、PLCβ2、TRPM5expression have reduced extend in the softpalate as well, even have reached significant difference compared with control group inindividual point; And the expressed of T1R3was significantly lower than controlgroup in the duodenum, the T1R3and TRPM5expression also has a tendency toreduced in the jejunum.In summary, estrogen increased the sensitivity to sweetness of the mice, make apreference for AK and sucrose solution at lower concentration. While with estrogendeficient mice, increased preference threshold of AK and sucrose solution, anddecreased preference ratios at low concentration AK and sucrose solution. The lake ofestrogrn make the expression of T1R3decreased significantly at the molecular andprotein level, and those of TRPM5、PLCβ2and Gα-gustducin have been inhibited tosome extend as well, implied that there is a multifaceted synergistic function in tasteregulation. This study would give a better understand of the estrogen to tasteperception and the related mechanism research.