Morrissey J J, Cohn D V
Endocrinology. 1978 Dec;103(6):2081-90. doi: 10.1210/endo-103-6-2081.
The preparation of dispersed parathyroid cells by collagenase digestion of porcine parathyroid glands, essentially as outlined by Brown et al. (Endocrinology 99: 1582, 1976), is described. The cells secrete parathormone linearly for at least 4 h of incubation and rapidly respond in inverse fashion to changes in the medium calcium and magnesium concentrations over the range 0.5-3.0 mM. In terms of inhibition of secretion, either ion was more effective in the presence of a minimum concentration of the other, indicating that calcium and magnesium affect separate cellular sites. Parathormone was identified both by immunoassay of the whole incubation medium and by its separation by polyacrylamide gels and carboxymethylcellulose chromatography. When the cells were incubated with radioactive amino acids and both the medium and cells were subsequently analyzed on gels, we found that parathyroid secretory protein as well as parathormone and some immunoactive fragments were present. Analysis of the radioactive protein contained in the cells at high and low calcium concentrations revealed that calcium decreased the formation of the secretory protein by approximately 40% without appreciably affecting the formation of proparathormone or parathormone. The secretion of both parathyroid secretory protein and parathormone were inversely proportional to the concentrations of medium calcium or magnesium. The secretion of the latter, however, was more sensitive (95% inhibition) than parathormone (40-60% inhibition) to changes in medium divalent cations. These results suggest that the synthesis, intracellular processing, or secretion of parathormone and parathyroid secretory protein utilize independent calcium- and magnesium-regulated pathways.
本文描述了按照Brown等人（《内分泌学》99: 1582, 1976）所述方法，通过胶原酶消化猪甲状旁腺来制备分散甲状旁腺细胞的过程。这些细胞在孵育至少4小时内呈线性分泌甲状旁腺激素，并在0.5 - 3.0 mM范围内对培养基中钙和镁浓度的变化迅速做出相反反应。就分泌抑制而言，在存在最低浓度的另一种离子时，任何一种离子的抑制效果都更显著，这表明钙和镁作用于不同的细胞位点。通过对整个孵育培养基进行免疫测定以及通过聚丙烯酰胺凝胶和羧甲基纤维素色谱分离来鉴定甲状旁腺激素。当细胞与放射性氨基酸一起孵育，随后对培养基和细胞进行凝胶分析时，我们发现存在甲状旁腺分泌蛋白以及甲状旁腺激素和一些免疫活性片段。对高钙和低钙浓度下细胞中所含放射性蛋白的分析表明，钙使分泌蛋白的形成减少了约40%，而对甲状旁腺激素原或甲状旁腺激素的形成没有明显影响。甲状旁腺分泌蛋白和甲状旁腺激素的分泌均与培养基中钙或镁的浓度成反比。然而，后者的分泌比甲状旁腺激素（40 - 60%抑制）对培养基中二价阳离子变化更敏感（95%抑制）。这些结果表明，甲状旁腺激素和甲状旁腺分泌蛋白的合成、细胞内加工或分泌利用了独立的钙和镁调节途径。
