Gerlach T H, Zile M H
Department of Food Science and Human Nutrition, Michigan State University, East Lansing 48824-1224.
J Lipid Res. 1991 Mar;32(3):515-20.
Tissue uptake and distribution of retinol from circulatory vitamin A transport complex was studied in order to determine the origin of the increased serum retinol in rats with short-term acute renal failure. In rats with acute renal failure, serum retinol increased 37-70% within 2 h after surgery. After an injection of donor plasma containing 1.8 muCi of [3H]retinol in retinol transport complex, in rats with renal failure the ability to clear radioactivity was decreased 36% by 0.5 h and 57% by 2 h, as compared to sham-operated rats. The uptake and distribution of radioactivity by nonrenal tissues was similar in rats with acute renal failure and with intact kidneys. The lack of renal function did not alter hepatic cycling of [3H]retinol from the circulation and thus could not account for the increased serum retinol in renal failure. When hepatic release of retinol-retinol binding protein was blocked by colchicine, the up-regulation of serum retinol, normally observed in rats with acute renal failure, was abolished. Our studies provide strong evidence that kidney has an important role in maintaining serum retinol homeostasis by influencing the release of retinol-retinol binding protein from liver into circulation. Peripheral tissue uptake of circulatory retinol and hepatic cycling of nonutilized retinol are not directly influenced by the kidney.
为了确定短期急性肾衰竭大鼠血清视黄醇增加的来源，研究了循环维生素A转运复合物中视黄醇的组织摄取和分布。在急性肾衰竭大鼠中，血清视黄醇在手术后2小时内增加了37 - 70%。与假手术大鼠相比，给肾衰竭大鼠注射含1.8μCi[3H]视黄醇的视黄醇转运复合物供体血浆后，0.5小时时清除放射性的能力降低了36%，2小时时降低了57%。急性肾衰竭大鼠和肾脏完整的大鼠非肾组织对放射性的摄取和分布相似。肾功能的缺失并未改变循环中[3H]视黄醇的肝脏循环，因此不能解释肾衰竭时血清视黄醇的增加。当秋水仙碱阻断视黄醇 - 视黄醇结合蛋白从肝脏的释放时，通常在急性肾衰竭大鼠中观察到的血清视黄醇上调被消除。我们的研究提供了有力证据，即肾脏通过影响视黄醇 - 视黄醇结合蛋白从肝脏释放到循环中，在维持血清视黄醇稳态方面发挥重要作用。循环视黄醇的外周组织摄取和未利用视黄醇的肝脏循环不受肾脏直接影响。
