Setoguti T, Inoue Y, Shin M
Department of Anatomy, Nagasaki University School of Medicine, Japan.
Cell Tissue Res. 1988 Mar;251(3):531-9. doi: 10.1007/BF00214000.
To determine both a threshold value of calcium concentration (CC) for the release of storage granules and that for the acceleration of degradation of these granules, the rat parathyroid glands were perfused in situ with HEPES-Ringer solutions containing different concentration of Ca2+ for 10 min. With perfusates containing 0.83-1.21 mM Ca2+ (equivalent to 8-11 mg/dl serum calcium), the number of type-I storage granules (large core) [NSG-I] and that of type-II storage granules (small core) [NSG-II] remained unchanged. With perfusates containing 0.83 mM Ca2+ (7.5 mg/dl) or less, however, both NSG-I and NSG-II decreased remarkably and the former was larger than the latter. On the contrary, with perfusates containing 1.27 mM Ca2+ (11.5 mg/dl) or more, NSG-II increased and the ratio of NSG-I to NSG-II was changed reversely. We concluded that a threshold value of CC required for the release of storage granules may be present between 0.88 and 0.83 mM Ca2+ (8 and 7.5 mg/dl) and that a threshold value of CC for accelerating the transformation of type-I granules into type-II, the degradation of storage granules, may be situated at about 1.27 mM Ca2+ (11.5 mg/dl). Additionally, it was suggested that both pro-secretory and storage granules are not only formed at the innermost Golgi cisterna but also at the trans-Golgi network.
为了确定储存颗粒释放的钙浓度（CC）阈值以及加速这些颗粒降解的阈值，将含有不同浓度Ca2+的HEPES - 林格溶液原位灌注大鼠甲状旁腺10分钟。当灌注液中Ca2+浓度为0.83 - 1.21 mM（相当于血清钙8 - 11 mg/dl）时，I型储存颗粒（大核心）数量[NSG - I]和II型储存颗粒（小核心）数量[NSG - II]保持不变。然而，当灌注液中Ca2+浓度为0.83 mM（7.5 mg/dl）或更低时，NSG - I和NSG - II均显著减少，且前者大于后者。相反，当灌注液中Ca2+浓度为1.27 mM（11.5 mg/dl）或更高时，NSG - II增加，NSG - I与NSG - II的比例发生反向变化。我们得出结论，储存颗粒释放所需的CC阈值可能存在于0.88至0.83 mM Ca2+（8至7.5 mg/dl）之间，而加速I型颗粒向II型颗粒转化（即储存颗粒降解）的CC阈值可能约为1.27 mM Ca2+（11.5 mg/dl）。此外，研究表明促分泌颗粒和储存颗粒不仅在高尔基体最内侧的潴泡形成，也在反式高尔基体网络形成。
