NPY and chronic kidney disease: Similarly, serum NPY, a sympathetic neurotransmitter with broad effects on the central nervous system, heart, bones, and kidneys,75,76 did not differ between ADPKD and healthy controls in the present series, but such parameter has been reported as increased only in later stages of CKD from other etiologies and not in ADPKD.77,78 Of note, uAGT, but not sAGT, was statistically higher in the ADPKD group versus controls, demonstrating greater activity of intrarenal RAAS.