Browsing by Author "Petrovic, Milos M. (57195967910)"

The aim of this study was to determine the mechanism of transport of 3-deazaguanine in the rat heart. We used single-pass, paired-tracer dilution method on isolated and retrogradely perfused rat hearts. The maximal cellular uptake (Umax) and total cellular uptake (Utot) of 3-deazaguanine were determined under control conditions and under influence of possible modifiers. Both Umax and Utot were significantly reduced in the presence of unlabeled 3-deazaguanine (from 19.57±2.02% to 8.14±1.19% and from 16.49±3.65% to 4.70±1.96%, n=6, respectively). The presence of pyrimidine nucleoside thymidine caused the reduction of both Umax and Utot (from 20.03±3.76% to 13.58±3.16% and from 16.43±3.58% to 11.94±3.13%, n=6, respectively). Also, we tested the effect of the absence of sodium ions in perfusion solution (both Umax and Utot significantly reduced from 17.95±2.73% to 16.67±2.16% and from 16.68±2.97% to 14.81±3.04%, n=6, respectively) and the effect of dinitrophenol (both Umax and Utot significantly reduced from 19.09±3.68% to 10.58±3.14% and from 16.86±3.84% to 7.10±3.11%, n=6, respectively). The results of self- and cross-inhibition studies show that the transport of 3-deazaguanine is saturable, energy- and sodium-dependent and that 3-deazaguanine uses endogenous transport systems for thymidine and adenosine for its own transport. © 2006 Akadémiai Kiadó, Budapest.

The aim of this study was to determine the mechanism of transport of 14C-thiamin in the hearts of healthy (non-alcoholic) and chronically alcoholic guinea pigs. We used the single-pass, paired-tracer dilution method on isolated and retrogradely perfused guinea pig hearts. The maximal cellular uptake (Umax) and total cellular uptake (Utot) of 14C-thiamin were determined under control conditions and under influence of possible modifiers. We tested how the presence of unlabeled thiamin, metabolic inhibitors, or absence of sodium ions influence the transport of 14C-thiamin. The results of our experiments show that the transport of 14C-thiamin is specific and energy-dependent and that its properties are significantly changed under the influence of chronic alcoholism. The latter effect occurs by increase in both Umax and Utot, as a manifestation of a compensatory mechanism in thiamin deficiency. © 2008 NRC.

The aim of this study was to determine the mechanism of transport of 14C-thiamin in the hearts of healthy (non-alcoholic) and chronically alcoholic guinea pigs. We used the single-pass, paired-tracer dilution method on isolated and retrogradely perfused guinea pig hearts. The maximal cellular uptake (Umax) and total cellular uptake (Utot) of 14C-thiamin were determined under control conditions and under influence of possible modifiers. We tested how the presence of unlabeled thiamin, metabolic inhibitors, or absence of sodium ions influence the transport of 14C-thiamin. The results of our experiments show that the transport of 14C-thiamin is specific and energy-dependent and that its properties are significantly changed under the influence of chronic alcoholism. The latter effect occurs by increase in both Umax and Utot, as a manifestation of a compensatory mechanism in thiamin deficiency. © 2008 NRC.