Westrick J A, Smolen A
Institute for Behavioral Genetics, University of Colorado, Boulder 80309-0447, USA.
Comp Biochem Physiol B Biochem Mol Biol. 1994 Oct-Nov;109(2-3):489-97. doi: 10.1016/0305-0491(94)90032-9.
Erythrocyte aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities are often used as indices of vitamin B-6 nutritional status; however, results using a mixed population of erythrocytes can be quite variable. Erythrocytes from two strains of mice (Mus domesticus), A/Ibg and DBA/Ibg, were separated according to age by centrifugation through discontinuous Percoll density gradients into three fractions: top (least dense, youngest), middle and bottom (most dense, oldest). A sufficient yield of age-fractionated erythrocytes was obtained from a single mouse for all of the enzyme measurements. The activities of AST, ALT and three age-marker enzymes, pyruvate kinase, acetylcholinesterase and hexokinase, were found to be significantly higher in the youngest cell fractions, and declined in the older, more dense fractions. A mice had significantly lower AST and ALT activities in the age separated fractions than did DBA mice. The measurement of enzyme activities in low density, young cells may be especially useful in studies involving conditions in which the proportion of young erythrocytes may be elevated with respect to the entire erythrocyte mass.
红细胞天冬氨酸氨基转移酶（AST）和丙氨酸氨基转移酶（ALT）活性常被用作维生素B-6营养状况的指标；然而，使用混合红细胞群体得到的结果可能差异很大。通过不连续的Percoll密度梯度离心，根据年龄将两种小鼠品系（小家鼠）A/Ibg和DBA/Ibg的红细胞分离为三个部分：顶部（密度最小，最年轻）、中部和底部（密度最大，最老）。从一只小鼠中获得了足够数量的按年龄分级的红细胞，用于所有酶的测量。发现AST、ALT以及三种年龄标记酶丙酮酸激酶、乙酰胆碱酯酶和己糖激酶的活性在最年轻的细胞部分显著更高，而在较老、密度更大的部分则下降。A品系小鼠在按年龄分离的部分中的AST和ALT活性显著低于DBA品系小鼠。在低密度、年轻细胞中测量酶活性在涉及年轻红细胞比例相对于整个红细胞群体可能升高的情况的研究中可能特别有用。
