This transporter has recently been cloned. Energy is expended directly only in the transport of sodium out of the cells. The exact form is not known and may vary among species. Organic anion secretion occurs primarily in the S2 segment of the proximal tubule. These now appear to be different modes of function of the same transporter which has recently been identified, cloned, and sequenced.
Energy is expended directly only in the transport of sodium out of the cells.