壳聚糖对低密度脂蛋白和脂蛋白(a)代谢的影响

Effects of poly- N -acetylglucosamine on metabolism of low density lipoprotein and lipoprotein(a)

目的 研究壳聚糖对低密度脂蛋白和脂蛋白 (a)代谢的影响。方法 壳聚糖经剌猬腋下静脉注入 ,2min后给予12 5I标记低密度脂蛋白、12 5I标记脂蛋白 (a)、12 5I标记去唾液酸低密度脂蛋白或12 5I标记去唾液酸脂蛋白 (a) ,1h后处死动物 ,测定血、肝、肾、脾、胆汁和肾上腺中的放射性含量。结果 实验发现肝对去唾液酸低密度脂蛋白和去唾液酸脂蛋白 (a)摄入均增加 ,但去唾液酸低密度脂蛋白被肝重新利用释放入血 ,而去唾液酸脂蛋白 (a)被大部分排出体外。由于肾和肾上腺亦能增加对去唾液酸低密度脂蛋白的摄取 ,因此不排除低密度脂蛋白受体参与去唾液酸低密度脂蛋白代谢 ,但去唾液酸脂蛋白 (a)和一部分去唾液酸低密度脂蛋白可能经去唾液酸脂蛋白相关受体代谢。壳聚糖能使肝和肾上腺对低密度脂蛋白的摄入增加 ,同时使血中低密度脂蛋白浓度降低 ,脾细胞对低密度脂蛋白的摄取也明显降低。结论 实验提示壳聚糖可能通过激活低密度脂蛋白受体起到降脂作用。

AIM To study the effects of poly- N -acetylglucosamine on the metabolism of low density lipoprotein and lipoprotein (a). METHODS Poly- N -acetylglucosamine was injected into the body of hedgehogs viathe armpit vein 2 minutes before the 125 I low density lipoprotein ( 125 I-LDL), 125 I lipoprotein(a) 〔 125 I-Lp(a)〕, 125 I desialylated low density lipoprotein ( 125 I-ds-LDL) or 125 I desialylated lipoprotein(a) 〔 125 I-ds-Lp(a)〕 were injected separatively . The animals were put to death in one hour. The radioactivity in the blood, liver, kidney, spleen, gall and adrenal were measured. RESULTS Absorption of ds-LDL and ds-Lp(a) increased in the liver. Later ds-LDL was reutilized and released into blood, but the majority of ds-Lp(a) was excreted out of the body from liver. It was not eliminated that ds-LDL was metabolized via the LDL receptor for the uptake of ds-LDL also increased in the kidney and the adrenal. It is possible that ds-Lp(a) and the part of ds-LDL may be catabolized via the desialylated lipoprotein-related receptor. Poly- N -acetylglucosamine could increase the absorption of LDL in the liver and the adrenal, meanwhile the concentration of LDL decreased in the blood and the absorption of LDL decreased in the spleen. CONCLUSION Poly- N -acetylglucosamine has the effects of lowering lipids through activating LDL receptor.