Fónagy A, Antal S, Holland J, Körösi L, Hidvégi E J
Radiat Res. 1985 Jul;103(1):34-45.
Previous investigations showed that when pregnant mice were exposed to a single whole-body dose of 0.5 Gy fission neutrons on Day 17 +/- 2 of gestation [H. H. Vogel, Jr. and S. Antal, Radiat. Res. 98, 52-64 (1984)] about 40% of the newborn mice died and the body and brain weights of surviving animals decreased by 30-35%. Decreases of body and brain weights were most prominent by the third week after birth, but the content of nucleic acids related to wet weight did not change in liver and brain upon irradiation [S. Antal, A. Fónagy, Z. Fülöp, E. J. Hidvégi, and H. H. Vogel, Jr. Int. J. Radiat. Biol. 46, 425-433 (1984)]. Studies presented in this paper show that after a single whole-body dose of 0.5 Gy neutron irradiation on Day 18 of pregnancy protein synthesis decreased in liver and brain of 3-week-old mice irradiated in utero. Incorporation of labeled amino acids in vivo into acid soluble nuclear proteins decreased by 15% in liver and by 40% in brain. It was significantly reduced into brain histones and certain brain nonhistone proteins (separated by two-dimensional electrophoresis). The amount of H1 and H4 brain histones decreased as well. Investigations with isolated protein synthesizing systems proved that the peptide bond formation was not impaired by irradiation. The aminoacylation of transfer-RNA, however, decreased in both liver and brain by 26-34 and 34-41%, respectively. Comparing the aminoacylation capacities in the two unirradiated organs, a much lower (about one-third) capacity was found in brain than in liver. Moreover, this low aminoacylation capacity of brain decreased further by about 40% after neutron irradiation. These results suggest that in the developing irradiated brain the reduced capacity of aminoacylation of transfer-RNA might be rate limiting for the efficiency of protein synthesis.
先前的研究表明，当怀孕小鼠在妊娠第17±2天接受单次全身剂量的0.5 Gy裂变中子照射时[小H. H. 沃格尔和S. 安塔尔，《辐射研究》98, 52 - 64 (1984)]，约40%的新生小鼠死亡，存活动物的体重和脑重下降了30 - 35%。出生后第三周体重和脑重的下降最为明显，但照射后肝脏和脑中与湿重相关的核酸含量没有变化[ S. 安塔尔、A. 福纳吉、Z. 富勒普、E. J. 希德韦吉和小H. H. 沃格尔，《国际辐射生物学杂志》46, 425 - 433 (1984)]。本文中的研究表明，在妊娠第18天接受单次全身剂量的0.5 Gy中子照射后，子宫内受照的3周龄小鼠肝脏和脑中的蛋白质合成减少。体内标记氨基酸掺入酸溶性核蛋白的量在肝脏中减少了15%，在脑中减少了40%。它显著减少进入脑组蛋白和某些脑非组蛋白（通过双向电泳分离）。脑H1和H4组蛋白的量也减少了。对分离的蛋白质合成系统的研究证明，肽键形成不受照射影响。然而，肝脏和脑中转移RNA的氨酰化分别下降了26 - 34%和34 - 41%。比较两个未受照器官的氨酰化能力，发现脑的能力比肝脏低得多（约三分之一）。此外，脑的这种低氨酰化能力在中子照射后进一步下降了约40%。这些结果表明，在发育中的受照脑中，转移RNA氨酰化能力的降低可能是蛋白质合成效率的限速因素。
