The glomerular filtration rate in the kidney is precisely regulated. The only way to adjust the filtration is what?
You can increase or decrease the filtration rate with hormones or drugs.
Naturally, Aldosterone and Vasopressin are hormones that can increase the GFR by reabsorbing sodium and water in the nephron (suppression of these hormones will deliver the opposite result). This will increase blood volume, osmolarity and renal perfusion. NSAIDs are drugs that can decrease GFR and renal perfusion by causing vasoconstriction of the nephron's arterioles.