成年男性体内苯丙氨酸通量：使用不同示踪剂及给药途径的估算

Phenylalanine flux in adult men: estimates with different tracers and route of administration.

作者信息

Krempf M, Hoerr R A, Marks L, Young V R

机构信息

Laboratory of Human Nutrition, Massachusetts Institute of Technology, Cambridge 02139.

出版信息

Metabolism. 1990 Jun;39(6):560-2. doi: 10.1016/0026-0495(90)90018-8.

DOI:10.1016/0026-0495(90)90018-8

PMID:2352476

Abstract

The kinetics of three different tracers of phenylalanine were studied when continuously infused together either by an intravenous (IV) or intragastric (IG) route in six young healthy men during a fasting state. During IV infusion, mean flux values were 39.2 +/- 1.8, 40 +/- 3, 41.8 +/- 3.6 mumol.kg-1.h-1 for L-[ring-2H5], [15N], and L-[1-13C]phenylalanine, respectively (differences not significant). Fluxes were higher (P less than .001) during IG than IV infusion, indicating a disappearance of tracer during the first pass through the splanchnic area. Also, higher fluxes were found for [ring-2H5]phenylalanine (74 +/- 6.23 mumol.kg-1.h-1) compared with [15N] and L-[1-13C]phenylalanine (54.24 +/- 4.7 and 61.15 +/- 5.3 mumol.kg-1.h-1) during IG infusion. Proton exchange might explain this difference, possibly limiting in vivo use of this label when the tracer is to be administered by the IG route.

摘要

在禁食状态下，对6名年轻健康男性通过静脉（IV）或胃内（IG）途径同时连续输注三种不同的苯丙氨酸示踪剂的动力学进行了研究。静脉输注期间，L-[环-2H5]、[15N]和L-[1-13C]苯丙氨酸的平均通量值分别为39.2±1.8、40±3、41.8±3.6 μmol·kg-1·h-1（差异不显著）。胃内输注时的通量高于静脉输注（P＜0.001），表明示踪剂在首次通过内脏区域时出现消失。此外，胃内输注期间，[环-2H5]苯丙氨酸的通量（74±6.23 μmol·kg-1·h-1）高于[15N]和L-[1-13C]苯丙氨酸（分别为54.24±4.7和61.15±5.3 μmol·kg-1·h-1）。质子交换可能解释了这种差异，当通过胃内途径给予示踪剂时，可能会限制该标记物在体内的使用。