Raila J, Buchholz I, Aupperle H, Raila G, Schoon H A, Schweigert F J
Institute of Nutritional Science, University Potsdam, Potsdam-Rehbrucke, Germany.
Vet Res. 2000 Nov-Dec;31(6):541-51. doi: 10.1051/vetres:2000138.
The contents of retinol and retinyl esters as well as retinol-binding protein (RBP) in the plasma, urine, liver and kidneys of dogs, raccoon dogs and silver foxes were investigated. In the plasma and urine of all three species, vitamin A was present as retinol and retinyl esters. Vitamin A levels (1376+/-669 microg x g(-1)) were significantly higher in the livers of dogs than in the kidneys (200+/-217 microg x g(-1), P < 0.001 ). However, vitamin A levels in the kidneys of raccoon dogs (291+/-146 microg x g(-1)) and silver foxes (474+/-200 microg x g(-1)) were significantly higher than in the liver (67+/-58 microg x g(-1) and 4.3+/-2.4 microg x g(-1), respectively, both P < 0.001). RBP was immunologically detected in the blood plasma of all species, but never in the urine. In the liver, immunoreactive RBP was found in hepatocytes. In the kidneys of all species, RBP was observed in the cells of the proximal convoluted tubules. The levels of vitamin A in the livers of raccoon dogs and silver foxes were extremely low, which would be interpreted as a sign of great deficiency in humans. This observation might indicate that the liver status cannot be used as an indicator of vitamin A deficiency in canines. The high levels of vitamin A in the kidneys in all three species may indicate a specific function of the kidney in the vitamin A metabolism of canines.
对狗、貉和银狐的血浆、尿液、肝脏和肾脏中的视黄醇、视黄酯以及视黄醇结合蛋白（RBP）含量进行了研究。在所有这三个物种的血浆和尿液中，维生素A以视黄醇和视黄酯的形式存在。狗肝脏中的维生素A水平（1376±669μg×g⁻¹）显著高于肾脏（200±217μg×g⁻¹，P<0.001）。然而，貉（291±146μg×g⁻¹）和银狐（474±200μg×g⁻¹）肾脏中的维生素A水平显著高于肝脏（分别为67±58μg×g⁻¹和4.3±2.4μg×g⁻¹，均P<0.001）。在所有物种的血浆中均通过免疫方法检测到了RBP，但在尿液中从未检测到。在肝脏中，在肝细胞中发现了免疫反应性RBP。在所有物种的肾脏中，在近端曲管的细胞中观察到了RBP。貉和银狐肝脏中的维生素A水平极低，这在人类中会被解释为严重缺乏的迹象。这一观察结果可能表明肝脏状态不能用作犬类维生素A缺乏的指标。所有三个物种肾脏中维生素A的高水平可能表明肾脏在犬类维生素A代谢中具有特定功能。
