Wolfrom G W, Asplund J M, Hoover T R
J Nutr. 1979 Feb;109(2):229-39. doi: 10.1093/jn/109.2.229.
A double cross-over experiment with 2 rumen-, bilateral jugular vein-, and portal vein-cannulated sheep was performed to determine the influence of route of infusion of methionine on nitrogen balance and blood amino acids. Nutrients were provided solely by intravenous (glucose, amino acids, water soluble vitamins) and intraruminal (VFA, minerals) infusion. Treatments consisted of the infusion of methionine plus serine via either the jugular vein (J) or portal vein (P). The respective order of treatments for the sheep were J, P, J, P and P, J, P, J. Urinary nitrogen was lower and nitrogen balance was greater when methionine was infused intrajugularly. No differences in plasma or blood urea nitrogen were noted. Plasma amino acid (PAA) concentrations showed no significant differences due to treatment. However, whole blood amino acid (BAA) concentrations revealed significantly greater levels of methionine when methionine was administered via the jugular vein. Expression of PAA as percentages of the total resulted in no treatment effects, while percentage expression of BAA showed that methionine was greater and phenylalanine was lower during intrajugular methionine infusion. The central and peripheral methionine infusion routes appeared to influence slightly the subsequent utilization of methionine as determined by effects on BAA levels of methionine. It was demonstrated that results from analysis of circulating amino acids may differ according to whether plasma or whole blood samples are used, and whether the data are expressed as concentrations or proportions.
对2只安装了瘤胃瘘管、双侧颈静脉瘘管和门静脉瘘管的绵羊进行了双交叉试验，以确定蛋氨酸输注途径对氮平衡和血液氨基酸的影响。营养物质仅通过静脉输注（葡萄糖、氨基酸、水溶性维生素）和瘤胃内输注（挥发性脂肪酸、矿物质）提供。处理包括通过颈静脉（J）或门静脉（P）输注蛋氨酸加丝氨酸。绵羊的处理顺序分别为J、P、J、P和P、J、P、J。颈静脉输注蛋氨酸时，尿氮较低，氮平衡较高。血浆或血尿素氮未见差异。血浆氨基酸（PAA）浓度因处理无显著差异。然而，全血氨基酸（BAA）浓度显示，通过颈静脉给药时蛋氨酸水平显著更高。以PAA占总量的百分比表示未产生处理效应，而BAA的百分比表示显示，颈静脉输注蛋氨酸期间蛋氨酸含量更高，苯丙氨酸含量更低。由对蛋氨酸BAA水平的影响所确定，蛋氨酸在中央和外周的输注途径似乎对蛋氨酸随后的利用有轻微影响。结果表明，根据使用的是血浆还是全血样本，以及数据是以浓度还是比例表示，循环氨基酸分析的结果可能会有所不同。
