cyclic-gmp and Glomerulonephritis--IGA

Topics: Cyclic GMP; Disease Progression; Endothelins; Glomerulonephritis, IGA; Glomerulonephritis, Membranoproliferative; Humans; Hypertension, Renal; Isosorbide Dinitrate; Nitric Oxide; Pilot Projects; Vasodilator Agents

Mediators and the effect of captopril on amino acid-induced hyperfiltration were studied. Acute intravenous L-arginine (arginine) infusion tests were performed twice, without captopril administration in 6 normal subjects (group I), before and after pretreatment with captopril in 10 normal subjects (group II) and 10 IgA nephropathy patients with slight renal dysfunction (group III). It was found that in all groups with and without captopril, arginine infusion led to a significant decrease in renal vascular resistance, and significant increases in renal plasma flow and plasma glucagon level. GFR was significantly increased in response to arginine only in normals without captopril pretreatment. Captopril pretreatment attenuated the rise in GFR following arginine infusion in normal subjects. Plasma renin activity and urinary cGMP were significantly increased in response to arginine only in normals without captopril pretreatment. No significant increase in urinary PGE2 was observed after arginine infusion in any groups. It was concluded that cGMP and glucagon are possible mediators for arginine-induced hyperfiltration and inhibition of renin-angiotensin system attenuates the arginine-induced rise in GFR.

Topics: Arginine; Captopril; Cyclic GMP; Dinoprostone; Female; Glomerular Filtration Rate; Glomerulonephritis, IGA; Glucagon; Humans; Male; Middle Aged; Renal Plasma Flow, Effective; Renin-Angiotensin System; Vascular Resistance

Topics: Adult; Age Factors; Creatine; Cyclic GMP; Female; Glomerulonephritis, IGA; Health; Humans; Male; Nitrites; Smoking

An endothelin urinary hyperexcretion, which is not counterbalanced by an adequate increase in cGMP biosynthesis, was previously detected in some patients with IgA Nephropathy (IgAN). Since this imbalance might potentiate local ET1-mediated hemodynamics effects, 9 IgAN patients with an increased (> or = 0.1) urinary ET1/cGMP ratio (group 1) and 5 IgAN patients with comparable renal function and reduced ET1/cGMP ratio (group 2) were given standard doses of isosorbide 5 mononitrate (as a nitric oxide source). Blood nitric oxide (NO) levels, as detected by electron paramagnetic resonance, significantly increased after isosorbide administration (p < 0.01) and decreased after drug discontinuation in both groups. Nitric oxide levels were significantly related with those of the effective renal plasma flow (p < 0.02), but not with the glomerular filtration rate. Proteinuria levels significantly decreased after drug administration (p < 0.009) in group 1 and returned to baseline levels thereafter, except two cases showing persisting low levels. Values of filtration fraction in the same group decreased after iso5M administration (p < 0.02 compared to basal levels). These results may possibly be related to the counterbalancing effects of nitric oxide on endothelin-mediated mesangial contraction.

Topics: Adult; Blood Pressure; Cyclic GMP; Electron Spin Resonance Spectroscopy; Endothelins; Female; Glomerulonephritis, IGA; Humans; Isosorbide Dinitrate; Male; Middle Aged; Nitric Oxide; Proteinuria; Vasodilator Agents