Oxalate uptake in fetal rat myoblasts

Oxalate uptake was studied in fetal rat myoblasts to attempt to define the characteristics of oxalate transport in myocardial cells. Oxalate uptake was found to be time, temperature and pH dependent and was inhibited by metabolic inhibitors (Dinitrophenol and iodoacetamide). Inhibition of oxalate uptake by 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) suggested transport by an anion exchange mechanism. Both chloride and sulfate inhibited oxalate uptake suggesting competition by both ions for a combined transporter. Although medium calcium concentration and calcium ionophores had no effect on oxalate uptake, the calcium channel blocker, nifedipine, significantly decreased oxalate uptake. Diacylglycerol (DAG) stimulated oxalate uptake, while forskolin had no effect. These studies suggest that myocardial cells transport oxalate by a mechanism similar to that described in renal epithelial cells. The uptake of oxalate by myocardial cells raises questions about the physiologic role of oxalate in myocardial cells and the mechanism of cardiac problems in primary hyperoxaluria.