Department of Environmental Biochemistry, Division of Biological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
Nutrients. 2020 Apr 2;12(4):990. doi: 10.3390/nu12040990.
The gustation system for sweeteners is well-known to be regulated by nutritional and metabolic conditions, but there is no or little information on the underlying mechanism. Here, we examined whether elevation of the blood glucose level was involved in alteration of the expression of sweet taste receptors in circumvallate papillae (CP) and sweet taste sensitivity in male Sprague-Dawley rats. Rats under 4 h-fed conditions following 18 h-fasting exhibited elevated blood glucose levels and decreased pancreatic T1R3 expression, compared to rats after 18 h-fasting treatment, and they exhibited increased protein expression of sweet taste receptors T1R2 and T1R3 in CP. Under streptozotocin (STZ)-induced diabetes mellites (DM) conditions, the protein expression levels of T1R2 and T1R3 in CP were higher than those under control conditions, and these DM rats exhibited increased lick ratios in a low sucrose concentration range in a brief access test with a mixture of sucrose and quinine hydrochloride (QHCl). These findings indicate that the elevation of blood glucose level is a regulator for an increase in sweet taste receptor protein expression in rat CP, and such alteration in STZ-induced DM rats is involved in enhancement of their sweet taste sensitivity.
甜味剂的味觉系统众所周知受到营养和代谢状况的调节，但对于其潜在机制还知之甚少。在这里，我们研究了血糖水平升高是否参与了在味觉乳头（CP）中甜味受体表达的改变和雄性 Sprague-Dawley 大鼠的甜味敏感性。与禁食 18 小时后的大鼠相比，禁食 18 小时后再给予 4 小时喂养的大鼠血糖水平升高，胰腺 T1R3 表达减少，并且 CP 中的甜味受体 T1R2 和 T1R3 的蛋白表达增加。在链脲佐菌素（STZ）诱导的糖尿病（DM）条件下，CP 中的 T1R2 和 T1R3 的蛋白表达水平高于对照条件，这些 DM 大鼠在含有蔗糖和盐酸奎宁（QHCl）的混合物的短暂接入测试中，在低蔗糖浓度范围内的舔舐比例增加。这些发现表明，血糖水平升高是大鼠 CP 中甜味受体蛋白表达增加的调节剂，而 STZ 诱导的 DM 大鼠中的这种改变参与了其甜味敏感性的增强。
