Mitrović D M, Rosić M A, Mojović M, Nestorović J, Kostić M
Institute of Physiology, Faculty of Medicine, Belgrade University, Serbia.
Arch Int Physiol Biochim Biophys. 1993 Nov-Dec;101(6):325-8. doi: 10.3109/13813459309046986.
The cellular uptake of (14C)-thiamin hydrochloride was studied in the isolated perfused guinea pig heart, using the rapid single circulation, paired-tracer technique, in which D-(3H)-mannitol serves as an extracellular marker. Cellular uptake of this vitamin was estimated by directly comparing venous dilution profiles of (14C) and (3H) radioactivities in the absence and presence of unlabelled thiamin hydrochloride and pyrithiamin hydrobromide. The maximal cellular uptake (Umax) of thiamin was very low (5.31 +/- 1.79%), while in the presence of 10 mM unlabelled thiamin and 1 mM pyrithiamin, Umax was significantly greater (9.71 +/- 1.57% and 12.30 +/- 0.82%, respectively). Our data suggest that there is a saturable mechanism of sarcolemmal thiamin transport out of myocardial cell, while this transport into the cell is unsaturable.
采用快速单循环、双示踪技术，以D-(3H)-甘露醇作为细胞外标志物，在离体灌流豚鼠心脏中研究了(14C)-盐酸硫胺素的细胞摄取。通过直接比较有无未标记盐酸硫胺素和氢溴酸吡硫胺存在时(14C)和(3H)放射性的静脉稀释曲线，估算该维生素的细胞摄取量。硫胺素的最大细胞摄取量（Umax）非常低（5.31±1.79%），而在存在10 mM未标记硫胺素和1 mM吡硫胺的情况下，Umax显著更高（分别为9.71±1.57%和12.30±0.82%）。我们的数据表明，心肌细胞膜存在可饱和的硫胺素转运机制将其转运出心肌细胞，而这种转运进入细胞是不饱和的。
