Klaude M, von der Decken A
Mech Ageing Dev. 1986 May;34(3):261-72. doi: 10.1016/0047-6374(86)90078-3.
The objective of this study was to determine whether ageing in the mouse is associated with changes in protein synthesis activity and response to dietary methionine-cysteine deficiency. Growing subadult mice (30-day-old) and adult mice (70-day-old) were compared. The amino acid restricted diet contained methionine and cysteine at a level of 10% that of the control diet. After a feeding period of 6 days protein synthesis activity was measured in liver, kidney and lung. In control liver, the level of protein synthesis activity was the same for the two age groups; in kidney and lung, activity was diminished in the adult group. After methionine-cysteine deficiency protein synthesis activity was unchanged in the subadult and diminished in the adult liver. In kidney, both age groups responded with an increase in activity. In lung, the subadult group remained unchanged and activity in the adult group was elevated. The amount of DNA/g wet weight of tissue was higher in the subadult than the adult group throughout. Methionine-cysteine deficiency resulted in an increase in DNA/g tissue wet weight, while the total amount of DNA in liver decreased, but was unchanged in kidney and lung. Total liver activity was decreased less in subadult than adult mice. Total kidney and lung activities were diminished in subadult but not adult mice. The results suggest that the specific protein synthesis activity of the ribosomes in the kidney and lung tends to decrease with age more readily than in liver, and that subadult liver displays less sensitivity towards methionine-cysteine deficiency than does adult liver.
本研究的目的是确定小鼠衰老是否与蛋白质合成活性的变化以及对饮食中蛋氨酸 - 半胱氨酸缺乏的反应有关。比较了幼年（30日龄）和成年（70日龄）的生长中小鼠。氨基酸限制饮食中蛋氨酸和半胱氨酸的含量为对照饮食的10%。经过6天的喂养期后，测量肝脏、肾脏和肺中的蛋白质合成活性。在对照肝脏中，两个年龄组的蛋白质合成活性水平相同；在肾脏和肺中，成年组的活性降低。蛋氨酸 - 半胱氨酸缺乏后，幼年组的蛋白质合成活性未变，成年肝脏中的活性降低。在肾脏中，两个年龄组的活性均增加。在肺中，幼年组保持不变，成年组的活性升高。整个幼年组组织每克湿重的DNA含量高于成年组。蛋氨酸 - 半胱氨酸缺乏导致每克组织湿重的DNA增加，而肝脏中的DNA总量减少，但在肾脏和肺中不变。幼年小鼠肝脏的总活性降低程度低于成年小鼠。幼年小鼠肾脏和肺的总活性降低，而成年小鼠则未降低。结果表明，肾脏和肺中核糖体的特定蛋白质合成活性比肝脏更容易随年龄增长而降低，并且幼年肝脏对蛋氨酸 - 半胱氨酸缺乏的敏感性低于成年肝脏。
