BIOCHEMICAL CHANGES IN RATS AS A FUNCTION OF AGE

随着生物体的老化，力量和活力往往会下降，这是 反映在生物体的生理和代谢活动中。老鼠， 不亚于人类，似乎表现出这些不断增加的特征 年龄。为了研究其中一些变化的生物化学， 雄性Fisher 344只，年龄从2到26个月不等。 处死动物，取出组织进行研究。血清样本来自于 大鼠去蛋白，测定游离氨基酸含量。 任何氨基酸的浓度都没有明显的趋势，即使 不同的大鼠之间有相当大的差异。平均而言， 任何给定氨基酸的浓度在很大程度上都是相同的。 年迈的老鼠和非常年轻的老鼠一样。几种酶的活性是 在肝脏匀浆中测量。甲酰还原酶(使用甲苯磺隆作为 A底物)随年龄增长而逐渐下降，而乳酸脱氢酶 基本保持不变。碱性磷酸酶和硫解酶较低 在幼年动物身上，并在它们到中年时上升(直到它们 大约12-16个月大)，然后随着动物变得 真的很老。

As organisms age there is often a decrease in strength and vigor which is reflected in the organism's physical and metabolic activities. Rats, no less than humans, seem to exhibit these characteristics of increasing age. In an effort to examine the biochemistry of some of these changes, male Fisher 344 rats of ages varying from two to twenty-six months were sacrificed and tissues were removed for study. Serum samples from the rats were deproteinized and the free amino acid content was determined. No trend was evident in the concentration of any amino acid even though there was considerable variation from rat to rat. On average, the concentration of any given amino acid was found to be the same in very old rats as it was in very young ones. Several enzyme activities were measured in liver homogenates. Carbonyl reductase (using metyrapone as a substrate) gradually declined with age whereas lactate dehydrogenase remained generally constant. Alkaline phosphatase and thiolase were low in young animals and rose as they reached middle age (until they were about 12-16 months old) and then declined again as the animals became really old.