Ali M, Mujoo K, Sahib M K
Brain Res. 1982 Dec;282(1):47-55. doi: 10.1016/0165-3806(82)90173-0.
Brain cells of newborn rat were found to synthesize and secrete alpha-fetoprotein (AFP) and albumin in short-term culture. Synthesis of AFP and albumin was demonstrated by time-related linear incorporation of [14C]leucine into immunoprecipitable AFP and albumin by brain cells from newborn rat during 6 h incubation of the cultures. Newly synthesized labeled AFP and albumin were also accumulated (secreted) linearly as a function of incubation period. Cycloheximide could inhibit this incorporation of [14C]leucine into immunoprecipitable AFP and albumin. Synthesis of AFP and albumin accounted for 11-13% and 5-6% respectively, while their secretion into the culture medium was about 27-30% and 11-13% respectively of the total proteins synthesized and secreted by brain cells of newborn rat. Rate of AFP synthesis was about 2-fold greater than that of albumin. AFP and albumin secreted by brain cells displayed a complete immunological identity with, and electrophoretic mobilities similar to, the serum AFP and albumin. Molecular weights of AFP and albumin secreted by brain cells were also similar to their corresponding serum proteins. AFP was identified as the only active estradiol binding protein secreted by newborn rat brain cells in culture. Our studies suggest that albumin and estrophilic AFP originate in the developing rat brain in situ by intracellular synthesis.
在短期培养中发现新生大鼠的脑细胞能合成并分泌甲胎蛋白（AFP）和白蛋白。通过在培养物6小时孵育期间，新生大鼠脑细胞将[14C]亮氨酸按时间相关的线性方式掺入可免疫沉淀的AFP和白蛋白中，证明了AFP和白蛋白的合成。新合成的标记AFP和白蛋白也随着孵育时间呈线性积累（分泌）。放线菌酮能抑制[14C]亮氨酸掺入可免疫沉淀的AFP和白蛋白中。AFP和白蛋白的合成分别占新生大鼠脑细胞合成和分泌总蛋白的11 - 13%和5 - 6%，而它们分泌到培养基中的量分别约为总蛋白的27 - 30%和11 - 13%。AFP的合成速率约为白蛋白的2倍。脑细胞分泌的AFP和白蛋白与血清AFP和白蛋白具有完全的免疫学同一性，且电泳迁移率相似。脑细胞分泌的AFP和白蛋白的分子量也与它们相应的血清蛋白相似。AFP被鉴定为培养的新生大鼠脑细胞分泌的唯一活性雌二醇结合蛋白。我们的研究表明，白蛋白和嗜雌激素性AFP通过细胞内合成在发育中的大鼠脑原位产生。
