The sodium-dependent multivitamin transporter (SMVT) also transports iodide. How important the SMVT is for iodide transport is not clear. Supplementing with biotin and pantothenic acid, however, could competitively block the transport of iodide by the SMVT. There is another transporter of of iodide, the sodium/iodide cotransporter, (SLC5A5) which is largely expressed in the thyroid. The SMVT is expressed in the digestive tract.