Khare S, Trivedi A, Kesavan P C, Prasad R
Int J Radiat Biol Relat Stud Phys Chem Med. 1982 Oct;42(4):369-83. doi: 10.1080/09553008214551301.
A decrease in the influx of several amino acids was observed following gamma-irradiation. At low dose (2.5 Gy), which does not affect cell survival, a stimulation in the uptake was visible; moreover, sulphydryl loss and lipid peroxidation were also evident. With further increase in the dose of radiation, a parallel increment in the loss of sulphydryl groups and production of malonaldehyde was observed. Radioprotectors like L-cysteine and dithiothreitol were shown to shield the radiation-induced loss of sulphydryl and damage to transport and survival. Reduced glutathione, on the other hand, exhibited protection at the level of sulphydryl damage only. N-ethylmaleimide, a well known hypoxic cell radiosensitizer, enhanced the radiosensitivity with respect to survival; it, however, had no effect on amino acid transport. Oxygen enhancement of radiation damage to transport and cell survival and the radioprotection by sodium formate under these circumstances, and more so by anoxia, were demonstrated. The results indicate that the manifestation of damage to membrane structure and function precedes any observable loss of survival.
γ射线照射后观察到几种氨基酸的流入减少。在不影响细胞存活的低剂量（2.5 Gy）下，摄取量有刺激作用；此外，巯基损失和脂质过氧化也很明显。随着辐射剂量的进一步增加，观察到巯基损失和丙二醛产生呈平行增加。像L-半胱氨酸和二硫苏糖醇这样的辐射防护剂被证明可以保护辐射诱导的巯基损失以及对转运和存活的损伤。另一方面，还原型谷胱甘肽仅在巯基损伤水平表现出保护作用。N-乙基马来酰亚胺是一种著名的乏氧细胞放射增敏剂，相对于存活而言增强了放射敏感性；然而，它对氨基酸转运没有影响。在这些情况下，证明了氧对转运和细胞存活的辐射损伤有增强作用，以及甲酸钠的辐射防护作用，缺氧时更是如此。结果表明，膜结构和功能损伤的表现先于任何可观察到的存活损失。
