Hyperglycemia inhibited taurine transport and taurine transporter gene expression in cultured rat cardiomyocytes / 中国应用生理学杂志

<p><b>AIM</b>To investigate the alterations of taurine transport, and taurine transporter (TAUT) mRNA by hyperglycemia in cultured rat cardiomyocytes.</p><p><b>METHODS</b>3H-taurine measured the amount of taurine uptake. TAUT mRNA consents were measured using quantitative RT-PCR.</p><p><b>RESULTS</b>The cellular uptake amounts of taurine in seven groups increased with incubation time, and near to be saturated after 5 min. The uptake amount of 10, 20, and 30 mmol/L glucose groups was obviously lower than that of the control group (P < 0.05 or P < 0.01). In 30 mmmol/L glucose, taurine release obviously was decreased, as compared with that of the control. Exposure of cells to 10, 20, and 30 mmmol/L glucose decreased taurine uptake in a concentration-dependent fashion. Exposure to hyperglycemia did not affect the Km of the TAUT, but the apparent Vmax were significantly decreased (P < 0.05). In 20 and 30 mmmol/L groups, TAUT mRNA contents of myocardial cells were significantly reduced, as compared with the control group (P < 0.05).</p><p><b>CONCLUSION</b>The data suggests that there are dysfunction of taurine uptake and downregulation of TAUT gene expression by glucose in cultured rat cardiomyocytes.</p>

An observation of taurine transport alterations in calcification of myocardial cells in vitro / 中国医学科学院学报

<p><b>OBJECTIVE</b>To observe the alterations of taurine transport, taurine transporter (TAUT) and cysteine sulfinate decarboxylase (CSD) mRNA in the calcification of myocardial cells in vitro.</p><p><b>METHODS</b>3H-taurine measured the amount of taurine uptake. TAUT and CSD mRNA consents were measured using competitive quantitative RT-PCR in cultured and calcified myocardial cells.</p><p><b>RESULTS</b>In calcification of myocardial cells, taurine concentration was decreased by 27% (P < 0.05), taurine uptake was markedly reduced, Vmax reduced by 39% (P < 0.01), there were no statistical significance of Km values between the two groups. TAUT mRNA decreased by 45% (P < 0.01), but CSD mRNA increased by 25% (P < 0.05).</p><p><b>CONCLUSIONS</b>The data suggest that there were impediment of taurine transport in calcification of myocardial cells, as TAUT mRNA level was decreased, but CSD mRNA concentration was improved.</p>