Ryan L M, Kurup I, Rosenthal A K, McCarty D J
Department of Medicine, Medical College of Wisconsin, Milwaukee 53226.
Arch Biochem Biophys. 1989 Aug 1;272(2):393-9. doi: 10.1016/0003-9861(89)90233-6.
Inorganic pyrophosphate elaboration by articular cartilage may favor calcium pyrophosphate dihydrate crystal deposition. Frequently crystal deposits form in persons affected with metabolic diseases. The cartilage organ culture system was used to model these metabolic conditions while measuring the influence on extracellular pyrophosphate elaboration. Alterations of ambient pH, thyroid stimulating hormone levels, and parathyroid hormone levels did not change pyrophosphate accumulation in the media. However, subphysiologic ambient calcium concentrations (25, 100, 500 microM) increased pyrophosphate accumulation about chondrocytes 3- to 10-fold. Low calcium also induced release of [14C]adenine-labeled nucleotides from chondrocytes, potential substrates for generation of extracellular pyrophosphate by ectoenzymes. Exposing cartilage to 10% fetal bovine serum also enhanced by 50% the egress of inorganic pyrophosphate from the tissue.
关节软骨产生的无机焦磷酸盐可能有利于二水焦磷酸钙晶体沉积。晶体沉积物常见于患有代谢性疾病的人。软骨器官培养系统被用来模拟这些代谢状况，同时测量对细胞外焦磷酸盐产生的影响。环境pH值、促甲状腺激素水平和甲状旁腺激素水平的改变并未改变培养基中焦磷酸盐的积累。然而，低于生理水平的环境钙浓度（25、100、500微摩尔）使软骨细胞周围的焦磷酸盐积累增加了约3至10倍。低钙还诱导软骨细胞释放[14C]腺嘌呤标记的核苷酸，这些核苷酸是外切酶产生细胞外焦磷酸盐的潜在底物。将软骨暴露于10%胎牛血清中也会使无机焦磷酸盐从组织中的流出增加50%。
