METABOLISM OF TRITIUM-LABELED AND C-14-LABELED ALANINE IN RATS
METABOLISM OF TRITIUM-LABELED AND C-14-LABELED ALANINE IN RATS
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DOI：
10.1152/ajpendo.1981.241.2.e121
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发表时间：
1981-01-01
影响因子：
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通讯作者：
KATZ, J
中科院分区：
文献类型：
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作者：
GOLDEN, S;CHENOWETH, M;KATZ, J
[3-3H]-丙氨酸和[U-14C]丙氨酸分别给药和连续输注。测定血清丙氨酸、葡萄糖和乳酸的比活性。丙氨酸的示踪动力学取决于示踪剂给药和取样的位置。示踪剂分别给予主动脉和腔静脉采血（A-VC模式）或示踪剂给予腔静脉和动脉采血（V-A模式）。当示踪剂以A-VC模式注入时，丙氨酸的平台比活性约为V-A模式的1/2。根据A-VC模式得到的比活性计算丙氨酸周转参数。计算的表观替代率平均为[U-14C]- 1.9 mg.cntdot.min-1.cntdot.kg-1， [3-3H]丙氨酸3.9 mg.cntdot.min-1.cntdot.kg-1，表明碳循环约为50%。丙氨酸碳对葡萄糖碳的表观贡献为15%。血浆水中的活性在注射[3-3H]丙氨酸后约5分钟达到最大，血液中[14C]葡萄糖的活性在注射[U-14C]丙氨酸后约10分钟达到最大。[3H]-和[14C]乳酸的最大比活性在注射后约1分钟内达到。根据连续输注结束后的洗脱曲线面积计算表观平均传递时间和丙氨酸质量。[3H]丙氨酸平均转运时间为10 min，丙氨酸表观总质量约为40 mg/kg。[U-14C]丙氨酸的平均表观传递时间为33-66分钟，对应于质量为100 mg/kg的丙氨酸或40 mg/kg的丙氨酸碳。
[3-3H]- and [U-14C]alanine were administered to starved rats by bolus injection and by continuous infusion. The specific activities of alanine, glucose and lactate in blood were followed. The tracer kinetics of alanine depended on the site of tracer administration and samping. Tracer was either administered into the aorta and blood sampled from the vena cava (A-VC mode) or tracer was administered into the vena cava and arterial blood sampled (V-A mode). When tracer was infused in the A-VC mode the plateau specific activity of alanine was about 1/2 that obtained in the V-A mode. The parameters of alanine turnover were calculated from the specific activities obtained in the A-VC mode. The calculated apparent replacement rate averaged 1.9 mg.cntdot.min-1.cntdot.kg-1 for [U-14C]- and 3.9 mg.cntdot.min-1.cntdot.kg-1 for [3-3H]alanine, indicating a carbon recycling of about 50%. The apparent contribution of alanine carbon to that of glucose is 15%. The maximal activity in plasma water is attained at about 5 min after bolus injection of [3-3H]alanine and that of [14C]glucose in blood is attained about 10 min after the injection of [U-14C]alanine. Maximal specific activity of [3H]- and [14C]lactate is attained within about 1 min after injection. The apparent mean transit time and alanine mass were calculated from the areas of washout curves after the continuous infusion was terminated. The mean transit time for [3H]alanine was 10 min and apparent total body mass of alanine of the order of 40 mg/kg. The apparent mean transit time for [U-14C]alanine ranged from 33-66 min corresponding to a mass of the order of 100 mg/kg of alanine or 40 mg/kg of alanine carbon.