Brock A A, Chapman S A, Ulman E A, Wu G
Department of Animal Science, Faculty of Nutrition, Texas A&M University, College Station 77843-2471.
J Nutr. 1994 Mar;124(3):340-4. doi: 10.1093/jn/124.3.340.
This study was designed to quantify the effect of dietary manganese deficiency on rat hepatic Mn concentration and arginase activity. Weanling male Sprague-Dawley rats were randomly assigned to two groups of nine rats each and fed L-amino acid diets with 0 or 48 micrograms Mn/g diet for 21 d. After 21 d, hepatic Mn concentration (mumol/g liver dry wt, mean +/- SEM) was 0.130 +/- 0.005 for the control group but was lower (P < 0.01) in the Mn-deficient group (0.040 +/- 0.003). There were no differences in the hepatic concentrations of any other measured mineral. Hepatic arginase activity [mmol ornithine/(g hepatic protein.min)] was 1.55 +/- 0.22 in the control group and was lower (P < 0.01) in the Mn-deficient group (1.12 +/- 0.26). Plasma ammonia concentration was 301 +/- 6 mumol/L in the control group and was higher (P < 0.01) in the Mn-deficient group (480 +/- 8 mumol/L). In contrast, plasma urea concentration was higher (P < 0.01) in the control group (350 +/- 10 mumol/L) than in the Mn-deficient group (267 +/- 7 mumol/L). There were no differences in plasma concentrations of arginine or other amino acids between the control and the Mn-deficient groups. Our results demonstrate for the first time that dietary Mn deficiency results in altered plasma concentrations of ammonia and urea in association with decreased hepatic Mn concentration and arginase activity in young growing rats.
本研究旨在量化膳食锰缺乏对大鼠肝脏锰浓度和精氨酸酶活性的影响。将断乳雄性Sprague-Dawley大鼠随机分为两组，每组9只，分别饲喂含0或48微克锰/克饲料的L-氨基酸饲料21天。21天后，对照组肝脏锰浓度（微摩尔/克肝脏干重，均值±标准误）为0.130±0.005，而锰缺乏组较低（P<0.01）（0.040±0.003）。所测的其他矿物质的肝脏浓度没有差异。对照组肝脏精氨酸酶活性[毫摩尔鸟氨酸/（克肝脏蛋白·分钟）]为1.55±0.22，锰缺乏组较低（P<0.01）（1.12±0.26）。对照组血浆氨浓度为每升301±6微摩尔，锰缺乏组较高（P<0.01）（480±8微摩尔/升）。相反，对照组血浆尿素浓度（350±10微摩尔/升）高于锰缺乏组（267±7微摩尔/升）（P<0.01）。对照组和锰缺乏组之间血浆精氨酸或其他氨基酸浓度没有差异。我们的结果首次表明，膳食锰缺乏会导致幼龄生长大鼠血浆氨和尿素浓度改变，同时肝脏锰浓度和精氨酸酶活性降低。
