Ikeda I, Nakagiri H, Sugano M, Ohara S, Hamada T, Nonaka M, Imaizumi K
Laboratory of Nutrition Chemistry, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Fukuoka, Japan.
Metabolism. 2001 Nov;50(11):1361-8. doi: 10.1053/meta.2001.26739.
Analysis of sterol composition in serum, liver, adipose tissue, adrenals, and abdominal aorta demonstrated that the contents of plant sterols, campesterol and sitosterol, were evidently higher in WKY and stroke-prone spontaneously hypertensive (SHRSP) rats than in Wistar and WKA rats fed a diet containing a 0.5% plant sterol mixture. Lymphatic 24-hour recovery of 3H-sitosterol was about 2-fold higher in the WKY and SHRSP rats than in the WKA rats. Lymphatic absorption of 14C-cholesterol was also higher in WKY and SHRSP rats compared with WKA rats, but the difference was smaller than in the case of sitosterol. The remarkable increase of sitosterol absorption in WKY and SHRSP rats was observed between 9 and 24 hours after the administration. In SHRSP rats, lymphatic absorption of sitosterol between 0 and 3 hours was also higher than those in the other rat strains. Markedly less esterified 3H-sitosterol was detected in lymph than 14C-cholesterol in all strains, and in WKY and SHRSP rats, only a small increase in the esterified forms of sitosterol and cholesterol was observed. Although the incorporation of micellar 3H-sitosterol and 14C-cholesterol into intestinal brush border membranes was higher in SHRSP rats than in WKA rats, no difference was observed between WKY and WKA rats. These observations suggest that the incorporation into the brush border membranes and the esterification of sterols are not the major determinants for the hyperabsorption of sitosterol and cholesterol in SHRSP and WKY rats. Secretion of sitosterol and cholesterol in the bile of rats fed a plant sterol mixture was lower in SHRSP than in WKA rats. These results suggest that WKY and SHRSP strains deposit plant sterols in the body by enhancing the absorption and lowering the excretion of plant sterols. These strains of rats may be suitable models for studying mechanisms of differential absorption of various sterols.
对血清、肝脏、脂肪组织、肾上腺和腹主动脉中的甾醇成分分析表明，WKY大鼠和易中风自发性高血压（SHRSP）大鼠体内的植物甾醇、菜油甾醇和谷甾醇含量明显高于喂食含0.5%植物甾醇混合物饮食的Wistar大鼠和WKA大鼠。WKY大鼠和SHRSP大鼠对3H-谷甾醇的淋巴24小时回收率比WKA大鼠高约2倍。与WKA大鼠相比，WKY大鼠和SHRSP大鼠对14C-胆固醇的淋巴吸收也更高，但差异比谷甾醇的情况小。在WKY大鼠和SHRSP大鼠中，给药后9至24小时观察到谷甾醇吸收显著增加。在SHRSP大鼠中，0至3小时内谷甾醇的淋巴吸收也高于其他大鼠品系。在所有品系中，淋巴中检测到的酯化3H-谷甾醇明显少于14C-胆固醇，在WKY大鼠和SHRSP大鼠中，仅观察到谷甾醇和胆固醇酯化形式的少量增加。尽管SHRSP大鼠中胶束3H-谷甾醇和14C-胆固醇掺入肠刷状缘膜的比例高于WKA大鼠，但WKY大鼠和WKA大鼠之间未观察到差异。这些观察结果表明，掺入刷状缘膜和甾醇的酯化不是SHRSP大鼠和WKY大鼠中谷甾醇和胆固醇吸收过多的主要决定因素。喂食植物甾醇混合物的大鼠胆汁中谷甾醇和胆固醇的分泌在SHRSP大鼠中低于WKA大鼠。这些结果表明，WKY大鼠和SHRSP大鼠品系通过增强植物甾醇的吸收和降低其排泄而在体内沉积植物甾醇。这些大鼠品系可能是研究各种甾醇差异吸收机制的合适模型。
