Ho K J
Proc Soc Exp Biol Med. 1975 Nov;150(2):271-7. doi: 10.3181/00379727-150-39018.
Forty-eight adult hamsters were divided equally into two groups fed a control diet and a 2% cholesterol diet, respectively, under a rigid lighting (6 PM-6 AM) and feeding (6 PM-8 AM) schedule for three weeks. The cholesterol synthetic activity of the liver, stomach, small intestine, cecum, colon and kidney was measured by in vivo conversion of acetate-1-14C to cholesterol in four animals each time at 4 hour intervals. A remarkable circadian rhythm with the peak at midnight and the nadir at noon was found in the liver of the control hamsters, but was completely abolished in the cholesterol-fed animals since the activity was nearly totally suppressed at all times. The small intestine exhibited a similar rhythm with the peak at midnight but maintained a high baseline activity from 8 AM to 6 PM. Cholesterol feeding did not alter the baseline activity but reduced 17% of the peak activity. Other organs failed to show such a circadian rhythm.
48只成年仓鼠被平均分为两组，分别喂食对照饮食和2%胆固醇饮食，在严格的光照（下午6点至上午6点）和喂食（下午6点至上午8点）时间表下持续三周。每隔4小时对每组中的4只动物进行检测，通过体内将乙酸盐-1-¹⁴C转化为胆固醇来测量肝脏、胃、小肠、盲肠、结肠和肾脏的胆固醇合成活性。在对照仓鼠的肝脏中发现了显著的昼夜节律，午夜达到峰值，中午降至最低点，但在喂食胆固醇的动物中这种节律完全消失，因为其活性在所有时间几乎都被完全抑制。小肠表现出类似的节律，午夜达到峰值，但在上午8点至下午6点保持较高的基础活性。喂食胆固醇并未改变基础活性，但使峰值活性降低了17%。其他器官未表现出这种昼夜节律。
