Final answer:
As GFR increases, the Na+ concentration of the filtrate reaching the DCT will decrease.
Step-by-step explanation:
As GFR (glomerular filtration rate) increases, the Na+ concentration of the filtrate reaching the DCT (distal convoluted tubule) will decrease. This is because an increase in GFR leads to a higher volume of filtrate passing through the renal tubules, resulting in less time for reabsorption of sodium ions. As a result, more sodium ions will be excreted in the urine. This is an important mechanism to maintain sodium balance in the body.