Bihler I, Charles P, Sawh P C
Can J Physiol Pharmacol. 1982 May;60(5):615-21. doi: 10.1139/y82-083.
Membrane transport of sugar and Ca2+ was studied in pigeon erythrocytes by measuring the cell to medium distribution of 3-O-[14C]methyl-D-glucose and 45Ca. We have found that stimulation of sugar transport by anoxia, adrenaline, or ascorbic acid was not dependent on external Ca2+, nor was it additive to the stimulatory effect of the calcium ionophore A23187. Stimulation by ascorbic acid was dependent on concentration and time. The slow basal 45Ca efflux was greatly accelerated by A23187, and this was further increased by adrenaline. A metabolic substrate mixture consisting of adenine, inosine, and fumarate (AIF) did not alter 45Ca efflux, except for antagonizing the effect of adrenaline in the presence of A23187. Sugar transport, whether basal or stimulated by adrenaline or ascorbic acid, was significantly decreased by AIF, independently of external Ca2+. Stimulation by A23187 in the absence of external Ca2+ was also antagonized by AIF. In cells depleted of Ca2+ by treatment with A23187 and EGTA, transport stimulation by adrenaline was abolished. These results suggest that release of Ca2+ from intracellular storage into the cytoplasm plays a role in the stimulation of sugar transport by adrenaline and anoxia and also by A23187 in the absence of external Ca2+. The data provide further indirect support for a calcium-dependent mechanism of sugar transport regulation in nucleated erythrocytes.
通过测量 3 - O - [¹⁴C]甲基 - D - 葡萄糖和⁴⁵Ca 在细胞与培养基之间的分布，研究了鸽红细胞中糖和 Ca²⁺的膜转运。我们发现，缺氧、肾上腺素或抗坏血酸对糖转运的刺激不依赖于细胞外 Ca²⁺，也不是钙离子载体 A23187 刺激作用的叠加。抗坏血酸的刺激作用依赖于浓度和时间。A23187 极大地加速了缓慢的基础⁴⁵Ca 外流，肾上腺素进一步增强了这种作用。由腺嘌呤、肌苷和富马酸组成的代谢底物混合物（AIF）除了在 A23187 存在时拮抗肾上腺素的作用外，不改变⁴⁵Ca 外流。无论基础糖转运还是由肾上腺素或抗坏血酸刺激的糖转运，AIF 均使其显著降低，且与细胞外 Ca²⁺无关。在无细胞外 Ca²⁺时，A23187 引起的刺激也被 AIF 拮抗。在用 A23187 和 EGTA 处理使细胞内 Ca²⁺耗竭的细胞中，肾上腺素对转运的刺激作用消失。这些结果表明，Ca²⁺从细胞内储存释放到细胞质中在肾上腺素、缺氧以及在无细胞外 Ca²⁺时 A23187 对糖转运的刺激中起作用。这些数据为有核红细胞中糖转运调节的钙依赖机制提供了进一步的间接支持。
