Basically, what occurs in the countercurrent multiplier process? basically, what occurs in the countercurrent multiplier process? uric acid is excreted into the kidney tubules while urea is reabsorbed in the nephron loop. creatinine is actively transported out of the blood into urine. glucose and sodium are cotransported from urine back into blood. sodium is pumped into the blood while potassium is actively transported out of the blood back into the tissues. a higher sodium concentration is produced in the renal medulla that osmotically draws out water, reducing it within the tubules and the urine.