BIOCHEMICAL CHANGES IN RATS AS A FUNCTION OF AGE

随着生物体年龄的增长，力量和活力通常会下降， 反映在机体的生理和代谢活动中。 老鼠，不 比人类少，似乎表现出这些不断增加的特征 年龄。 为了检查其中一些变化的生物化学， 雄性 Fisher 344 只年龄从 2 个月到 26 个月不等的大鼠 处死并取出组织用于研究。 血清样本取自 对大鼠进行脱蛋白并测定游离氨基酸含量。 尽管任何氨基酸的浓度没有明显的趋势 大鼠与大鼠之间存在相当大的差异。 平均而言， 发现任何给定氨基酸的浓度在非常大的范围内是相同的 老老鼠和年轻老鼠一样。 几种酶的活性 在肝脏匀浆中测量。 羰基还原酶（使用美替拉酮作为 底物）随着年龄的增长而逐渐下降，而乳酸脱氢酶 基本保持不变。 碱性磷酸酶和硫解酶低 在年轻的动物中，当它们到达中年时就会上升（直到它们 大约 12-16 个月大），然后随着动物变得 真的老了。 在肝脏匀浆中测量的脂肪酸被发现 到中年再增加，然后下降。 然而，亚麻酸却 随年龄变化不大。

As organisms age there is often 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. Fatty acid, measured in liver homogenates, were found to increase to middle age and then to decline. Linolenic acid, however, did not vary much with age.