Lutton C, Perrodin M, Cardona-Sanclemente L E, Sérougne C
Reprod Nutr Dev (1980). 1986;26(6):1241-53. doi: 10.1051/rnd:19860902.
Sterol radioactivity was measured in the gastrointestinal tract of rats fed a semi-purified basal diet (B), either enriched with 0.5% cholesterol (CH) or containing 2% orotic acid (O). These measurements were taken after a fast of 48 h (CHF) or after fasting and 4-aminopyrazolopyrimidine (APP) treatment (CHFA); the five groups were killed 70 min after a subcutaneous injection of [1-14C]-acetate. Since these results agree with current published data, it is suggested that, although this method is not quantitative, it can give accurate estimates of the qualitative variations of cholesterogenesis in one organ. Adding cholesterol to the diet had no effect on sterogenesis in the stomach and caecum-colon. Fasting for 48 h did not affect cholesterogenesis in the caecum-colon, but stomacal sterogenesis was reduced (50%). APP treatment, which did not affect cholesterogenesis in the stomach, strongly stimulated (4-fold) cholesterogenesis in the caecum-colon. A slight decrease (30%) in intestinal cholesterogenesis was observed after a cholesterol-rich diet. This decrease occurred mainly in villus enterocytes. Fasting reduced cholesterol synthesis 2 to 4-fold mainly in the proximal intestine, while APP treatment stimulated it until a level higher than in nourished control rats. The level of cholesterogenesis was similar in all the enterocytes collected from duodenum to ileum in APP-treated rats. Since there was high mucosa cell loss (about 50%) during the 48-hour APP treatment, total intestinal cholesterogenesis in the CHFA rats was not higher than in the CH animals. Under the present physiological conditions, the feedback inhibition of intestinal cholesterogenesis by luminal bile acids was not clear, while that by luminal cholesterol or by LDL-cholesterol penetrating by specific receptors was modest over a wide range of physiological conditions.
在喂食半纯化基础日粮（B）的大鼠胃肠道中测量甾醇放射性，该日粮要么添加0.5%胆固醇（CH），要么含有2%乳清酸（O）。这些测量是在禁食48小时后（CHF）或禁食并经4-氨基吡唑并嘧啶（APP）处理后（CHFA）进行的；五组大鼠在皮下注射[1-14C]-乙酸盐70分钟后处死。由于这些结果与当前已发表的数据一致，因此表明，尽管该方法不是定量的，但它可以准确估计一个器官中胆固醇生物合成的定性变化。在日粮中添加胆固醇对胃和盲肠-结肠中的甾醇生成没有影响。禁食48小时不影响盲肠-结肠中的胆固醇生物合成，但胃中的甾醇生成减少（50%）。APP处理对胃中的胆固醇生物合成没有影响，但强烈刺激（4倍）盲肠-结肠中的胆固醇生物合成。在富含胆固醇的日粮后，观察到肠道胆固醇生物合成略有下降（30%）。这种下降主要发生在绒毛肠上皮细胞中。禁食主要使近端肠道中的胆固醇合成减少2至4倍，而APP处理则刺激其合成，直至高于正常喂食的对照大鼠。在APP处理的大鼠中，从十二指肠到回肠收集的所有肠上皮细胞中的胆固醇生物合成水平相似。由于在48小时的APP处理过程中有大量黏膜细胞损失（约50%），CHFA大鼠的总肠道胆固醇生物合成并不高于CH组动物。在目前的生理条件下，管腔胆汁酸对肠道胆固醇生物合成的反馈抑制不明确，而管腔胆固醇或通过特定受体渗透的低密度脂蛋白胆固醇在广泛的生理条件下的反馈抑制作用较小。
