Collins J M
J Biol Chem. 1978 Aug 25;253(16):5769-73.
The DNA content of mature rat liver parenchymal cells falls into three distinct classes with 1:2:4 amounts of DNA. These classes represent 2 N, 4 N, and 8 N cells. We have measured the changing proportions of these cells from 0.75 to 24 months of age. We have obtained a useful approximation for the numbers of each ploidy class, for cellular preparations from liver, as a function of the amount of DNA and age. Multiple linear regression analysis revealed that the average DNA content per cell is given by the relationship DNA/cell = 41.28(1/2)--324.14 Age1/4 + 499.37 Age1/8--207.24, with a multiple correlation coefficient of 0.990. Measurements of the amount of RNA synthesized in a 15-min period revealed that the relative proportions were 1.2:1.0 for 4 N:2 N cells of young rats, 1.3:1.1.:1.0 for 8 N:4 N:2 N cells of intermediate ages, and 1.1:1.0 for 8 N:4 N cells of old rats. The absolute amounts of RNA synthesized by each ploidy class declined with age.
成熟大鼠肝脏实质细胞的DNA含量分为三类，其DNA含量比例为1:2:4。这些类别分别代表2N、4N和8N细胞。我们测量了从0.75个月到24个月大的这些细胞比例的变化。我们得到了一个关于肝脏细胞制备中每个倍性类别的细胞数量的有用近似值，它是DNA含量和年龄的函数。多元线性回归分析表明，每个细胞的平均DNA含量由以下关系给出：DNA/细胞 = 41.28(1/2) - 324.14年龄1/4 + 499.37年龄1/8 - 207.24，复相关系数为0.990。在15分钟内合成的RNA量的测量结果显示，幼鼠4N:2N细胞的相对比例为1.2:1.0，中年8N:4N:2N细胞的相对比例为1.3:1.1:1.0，老年8N:4N细胞的相对比例为1.1:1.0。每个倍性类别合成的RNA绝对量随年龄下降。
