URINARY NITRIC-OXIDE SYNTHASE ACTIVITY AND CYCLIC-GMP LEVELS ARE DECREASED WITH INTERSTITIAL CYSTITIS AND INCREASED WITH URINARY-TRACT INFECTIONS

Purpose: Since urinary nitric oxide synthase (NOS) activity correlates with certain disease processes affecting the urinary tract and since nitric oxide increases cyclic GMP levels by activating guanylyl cyclas e, urinary particulate NOS activity and cyclic GMP levels are evaluate d in female patients with interstitial cystitis (IC) and compared with those from female controls and female patients with urinary tract inf ections (UTIs). Materials and Methods: Urinary NOS activity is measure d as the formation of [C-14]-L-citrulline from [C-14]-L-arginine, and urinary cyclic GMP levels are measured by an [I-125]-radioimmunoassay. Results: Female patients with IC have significantly less NOS activity in their urine pellet particulate fractions than female controls or f emales with UTIs, 2.3 +/- 1.0, 14 +/- 3.0, and 120 +/- 10 pmol. citrul line formed/min./mg. protein. Urinary cyclic GMP levels also are signi ficantly lower in IC patients than in female controls or females with UTIs: 0.50 +/- 0.06, 0.82 +/- 0.14, and 3.72 +/- 0.81 mu mol. cyclic G MP/g. creatinine. Conclusion: Regulation of urinary NOS activity with subsequent changes in nitric oxide and cyclic GMP may be an important determinant of symptoms and immunologic responses to UTIs and IC.