Possible function of estrogen on the taste transduction system.

本研究首次用免疫印迹分析和免疫组织化学方法研究了类固醇合成关键酶细胞色素P450侧链裂解酶(P450scc)和P450芳香酶在大鼠环状乳突味蕾中的定位和表达模式。免疫印迹分析表明，在大鼠肾上腺细胞色素P450scc和大鼠卵巢细胞色素P450芳香酶的分子量接近的蛋白质中，存在于大鼠的环状乳头中。在免疫组织化学中，针对细胞色素P450scc和P450芳香酶的抗体产生了味蕾细胞亚群的标记。在P450scc与α-Gustducin或磷脂酶Cβ2(β2)的双重免疫标记中，P450scc在α-Gustducin或PLCβ2的亚群中共表达，但不共表达主要的III型细胞标志神经黏附分子(NCAM)。进一步的双免疫标记研究表明，P450芳香酶在α-Gustducin或PLCβ2的一个子集中共表达，但不共表达大多数III型细胞的标志PGP9.5。细胞色素P450scc和P450aromatase的选择性定位强烈地表明，胆固醇生物合成雌激素可能发生在大鼠味蕾的II型细胞亚群中。尽管雌激素在味蕾功能中的全部意义尚不清楚，但雌激素似乎是味觉转导的重要调节因子，就像ATP(Finger等人，2005年)的情况一样，这进一步支持了味觉细胞在味蕾生活中的中心地位。

The present study demonstrated for the first time the localization and pattern of expression of key enzymes for steroidogenesis, cytochrome P450 side-chain-cleavage (P450scc) and P450 aromatase, in the taste buds of rat circumvallate papillae, using immunoblot analyses and immunohistochemistry. Immunoblot analyses showed that proteins with a molecular weight close to that of rat adrenal cytochrome P450scc and a molecular weight close to that of rat ovary cytochrome P450 aromatase were present in the rat circumvallate papillae. In immunohistochemistry, antibodies against cytochrome P450scc and P450aromatase yielded the labelings of a subset of taste bud cells. In double immunolabeling of P450scc and α-gustducin or phospholipase Cβ2 (PLCβ2), which were considered as markers of a majority of type II cells, P450scc co-expressed in a subset of α-gustducin or PLCβ2, but did not co-express major type III cell marker, neural adhesion molecule (NCAM). Further double immunolabeled studies showed that P450aromatase co-expressed in a subset of α-gustducin or PLCβ2, but did not co-express PGP9.5, a marker of a majority of type III cell. The selective localization of cytochrome P450scc and P450aromatase strongly suggests that estrogen biosynthesis from cholesterol might occur in a subset of type II cells of the rat taste buds. Although the full significance of estrogens in the taste bud function is not yet understand, estrogens appears to be an important regulator of taste transduction, as is the case with ATP (Finger et al., 2005), which further supports the centrality of taste cells in the life of taste buds.