Krause B R, Sloop C H, Castle C K, Roheim P S
J Lipid Res. 1981 May;22(4):610-9.
Rat mesenteric lymph contains all serum apolipoproteins. However, it is uncertain whether some of these apolipoproteins are derived from intestinal synthesis or are transferred from plasma. We compared lymph apolipoprotein composition, concentrations, and transport rates in normal rats and in rats treated with pharmacologic doses of ethinyl estradiol which have negligible concentrations of serum lipids and apolipoproteins. Lymph apolipoproteins were examined before and after duodenal lipid infusion. Lymph d less than 1.006 and 1.006-1.21 g/ml lipoproteins were isolated and SDS-electrophoresis was performed using 10 and 3.5% polyacrylamide. During lipid absorption, lymph flow increased in control but not in treated rats. Control lymph contained all major apolipoproteins, but lymph from ethinyl estradiol-treated rats contained only apoB, A-I, and A-IV. Two apoB bands were noted on 3.5% gels in control lymph, but only the lower molecular weight protein was found in lymph from ethinyl estradiol-treated rats. In control rats, transport rates for apoA-I, A-IV, E, and C proteins increased during lipid absorption, but only in the case of A-IV was this a reflection of increased apolipoprotein concentration and not the enhanced lymph flow. In ethinyl estradiol-treated rats only the A-IV transport rate increased due to lipid infusion. It is concluded that in the ethinyl estradiol-treated rat 1) the intestine does not synthesize apoE, C, or the high molecular weight apoB; 2) lymphatic output of A-IV is predominantly increased during lipid absorption; and 3) since plasma apolipoprotein concentrations are negligible, lymph lipoproteins from ethinyl estradiol-treated rats may represent a close approximation to nascent particles of intestinal origin.
大鼠肠系膜淋巴液中含有所有血清载脂蛋白。然而，这些载脂蛋白中的某些是来源于肠道合成还是从血浆转移而来尚不确定。我们比较了正常大鼠以及用药理剂量炔雌醇处理的大鼠（其血清脂质和载脂蛋白浓度可忽略不计）的淋巴载脂蛋白组成、浓度和转运速率。在十二指肠脂质输注前后检测淋巴载脂蛋白。分离出密度小于1.006和1.006 - 1.21 g/ml的淋巴脂蛋白，并用10%和3.5%的聚丙烯酰胺进行SDS电泳。在脂质吸收过程中，对照大鼠的淋巴液流量增加，而处理过的大鼠则未增加。对照淋巴液含有所有主要载脂蛋白，但炔雌醇处理过的大鼠的淋巴液仅含有载脂蛋白B、A - I和A - IV。在对照淋巴液的3.5%凝胶上观察到两条载脂蛋白B条带，但在炔雌醇处理过的大鼠的淋巴液中仅发现较低分子量的蛋白质。在对照大鼠中，脂质吸收期间载脂蛋白A - I、A - IV、E和C蛋白的转运速率增加，但仅就A - IV而言，这是载脂蛋白浓度增加的反映，而非淋巴液流量增加所致。在炔雌醇处理过的大鼠中，仅A - IV的转运速率因脂质输注而增加。结论是，在炔雌醇处理过的大鼠中：1）肠道不合成载脂蛋白E、C或高分子量的载脂蛋白B；2）脂质吸收期间A - IV的淋巴输出主要增加；3）由于血浆载脂蛋白浓度可忽略不计，炔雌醇处理过的大鼠的淋巴脂蛋白可能非常接近肠道来源的新生颗粒。
