Villalobos C, Alonso-Torre S R, Núñez L, García-Sancho J
Instituto de Biología Genética Molecular, Universidad de Valladolid, Spain.
Am J Physiol. 1997 Dec;273(6):C1963-71. doi: 10.1152/ajpcell.1997.273.6.C1963.
The effects of ATP and other nucleotides on the cytosolic Ca2+ concentration ([Ca2+]i) of single immunocytochemically typed anterior pituitary (AP) cells have been studied. ATP increased [Ca2+]i in a large percentage (60-88%) of all five AP cell types: lactotropes, somatotropes, corticotropes, gonadotropes, and thyrotropes. Additivity experiments suggest the presence of at least two different receptors, one accepting both ATP and UTP (U receptor), producing Ca2+ release from the intracellular stores, and the other preferring ATP (A receptor), producing Ca2+ (and Mn2+) entry. The characteristics of the U and A receptors were consistent with those of P2Y2 and P2X2, respectively, and their distribution in the different AP cell types was not homogeneous. The presence of other ATP receptors such P2Y1 or P2X2/P2X3 heteropolymers in a small fraction of the cells cannot be excluded. Thus functional ionophoric P2X receptors, which are typical of neural tissue, are also present in the pituitary gland and could contribute to regulation of the gland's function.
已对ATP和其他核苷酸对单一免疫细胞化学分型的垂体前叶（AP）细胞胞质Ca2+浓度（[Ca2+]i）的影响进行了研究。ATP使所有五种AP细胞类型（催乳素细胞、生长激素细胞、促肾上腺皮质激素细胞、促性腺激素细胞和促甲状腺激素细胞）中的大部分（60 - 88%）细胞的[Ca2+]i升高。加和性实验表明至少存在两种不同的受体，一种同时接受ATP和UTP（U受体），促使Ca2+从细胞内储存库释放，另一种更倾向于ATP（A受体），促使Ca2+（和Mn2+）内流。U受体和A受体的特性分别与P2Y2和P2X2一致，且它们在不同AP细胞类型中的分布并不均匀。不能排除一小部分细胞中存在其他ATP受体，如P2Y1或P2X2/P2X3异聚体。因此，典型的神经组织功能性离子通道型P2X受体也存在于垂体中，并可能有助于调节垂体功能。
