Quamme G, Pfeilschifter J, Murer H
Department of Medicine, University of British Columbia, Vancouver, Canada.
Biochem Biophys Res Commun. 1989 Feb 15;158(3):951-7. doi: 10.1016/0006-291x(89)92814-3.
Dose-dependent inhibition of Na/phosphate cotransport by parathyroid hormone (PTH) was correlated with the generation of hormone-mediated second messengers, cAMP, 1,2-diacylglycerol and inositol 1,4,5 trisphosphate in an established epithelial cell line (opossum kidney (OK) cells). PTH results in a dose-dependent decline in Na/phosphate cotransport with a half-maximal response at about 10(-11) M. This hormone concentration is commensurate with the levels required to increase 1,2-diacylglycerol and inositol 1,4,5-trisphosphate concentrations by about half maximal but not with those needed for cAMP generation (10(-9) to 10(-8) M PTH). Accordingly, activation of phospholipase C may be physiologically more important than stimulation of adenylate cyclase at normal PTH levels.
甲状旁腺激素（PTH）对钠/磷酸盐协同转运的剂量依赖性抑制作用，与一种已建立的上皮细胞系（负鼠肾（OK）细胞）中激素介导的第二信使环磷酸腺苷（cAMP）、1,2 -二酰甘油和肌醇1,4,5 -三磷酸的生成相关。PTH导致钠/磷酸盐协同转运呈剂量依赖性下降，在约10^(-11) M时出现半数最大反应。该激素浓度与使1,2 -二酰甘油和肌醇1,4,5 -三磷酸浓度增加约半数最大所需的水平相当，但与cAMP生成所需的浓度（10^(-9)至10^(-8) M PTH）不同。因此，在正常PTH水平下，磷脂酶C的激活在生理上可能比腺苷酸环化酶的刺激更为重要。
