The diagram below shows a simplified schematic of a single nephron in a human kidney.
A class of drugs called SGLT2 inhibitors is used to treat type 2 diabetes. These drugs work by selectively inhibiting the sodium-glucose co-transporters responsible for reabsorbing glucose back into the blood from the filtrate.
In which labeled region of the nephron do these co-transporters normally function, and what would be the effect of an SGLT2 inhibitor on the water potential (ψ\psiψ) of the filtrate leaving this region?
Region YYY; filtrate water potential is higher (less negative)
Region ZZZ; filtrate water potential is lower (more negative)
Region XXX; filtrate water potential is lower (more negative)
Region XXX; filtrate water potential is higher (less negative)