Idahl L, Sehlin J, Täljedal I, Tamarit-Rodriguez J
Acta Endocrinol (Copenh). 1978 May;88(1):113-21. doi: 10.1530/acta.0.0880113.
Valinomycin, 0.5-500 nM, was tested for its effects on pancreatic islets microdissected fron non-inbred ob/ob-mice. Valinomycin decreased the islet accumulation Rb+ and the content of ATP in a dose-dependent manner; efflux of Rb+ from pre-loaded islets was not noticeably changed. Rb+ accumulation and ATP content correlated markedly; on the model of linear regression, less than 10% of the change Rb+ accumulation in valinomycin-treated islets was statistically attributable to factors other than ATP. Valinomycin did not cause a prompt inhibition of glucose-stimulated insulin release that could reflect hyperpolarization due to increased K+ permeability. The following conclusions are drawn: 1) The plasma membranes of beta-cells resemble those of neurons in having such a high ion permeability as to be relatively little influenced by valinomycin; 2) Islet accumulation of Rb+ is due to a vectorial catalyst in theplasma membrane rather than to uptake by mitochondria; 3) Rb+ accumulation in islets is ATP-dependent.
对0.5 - 500纳摩尔的缬氨霉素进行了测试，观察其对从非近交系ob/ob小鼠分离的胰岛的影响。缬氨霉素以剂量依赖的方式降低了胰岛对Rb⁺的摄取以及ATP的含量；预先加载Rb⁺的胰岛中Rb⁺的外流没有明显变化。Rb⁺摄取和ATP含量显著相关；在线性回归模型中，缬氨霉素处理的胰岛中Rb⁺摄取变化的不到10%在统计学上可归因于ATP以外的因素。缬氨霉素不会立即抑制葡萄糖刺激的胰岛素释放，而这种抑制可能反映了由于钾离子通透性增加导致的超极化。得出以下结论：1）β细胞的质膜与神经元的质膜相似，具有很高的离子通透性，因此受缬氨霉素的影响相对较小；2）胰岛对Rb⁺的摄取是由于质膜中的一种载体催化剂，而不是线粒体的摄取；3）胰岛中Rb⁺的摄取依赖于ATP。
