title: Blunted response of the renin-angiotensin system and nitric oxide synthesis related to sodium sensitivity in immunoglobulin A nephropathy.
abstract: Sodium sensitivity of blood pressure appears before hypertension in immunoglobulin A nephropathy, as glomerulosclerosis and interstitial damage progress. To find whether this sensitivity is related to NO and the renin-angiotensin system, we examined 39 such patients without hypertension after they followed a diet with an ordinary sodium level for 1 week and a sodium-restricted diet for 1 week, in random order. Patients were divided into two groups at the median of their sodium sensitivity index (<0.040, n=19; > or =0.040 mmHg/mEq per day, n=20), calculated as the reciprocal of the slope of the pressure-natriuresis curve drawn by linkage of two datum points obtained during the different diets. Urinary excretion of NOx (NO2 and NO3), plasma renin activity, and serum aldosterone were measured. NOx was higher in the low-index group than in the high-index group with the ordinary sodium level, but not during sodium restriction. NOx was correlated negatively and significantly with the index with the ordinary sodium level (p=-0.406), but correlation in changes during sodium loading was not significant (p=-0.195). Changes in plasma renin activity and serum aldosterone during sodium restriction were greater in the low-index group than in the high-index group. The changes in renin activity and aldosterone were correlated negatively and significantly with the index (p=-0.573 and -0.499, respectively). These results indicate that impairment of NO synthesis and a blunted response of the renin-angiotensin system are attributable to the altered sodium sensitivity of blood pressure in patients with immunoglobulin A nephropathy.
authors.affiliation: Department of Internal Medicine, Osaka City General Hospital, Osaka, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Konishi
authors.forename: Takashi
authors.initials: T
authors.lastname: Morikawa
authors.forename: Takanori
authors.initials: T
authors.lastname: Yasu
authors.forename: Kae
authors.initials: K
authors.lastname: Teramoto
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Okada
authors.forename: Katsunobu
authors.initials: K
authors.lastname: Yoshioka
authors.forename: Michiaki
authors.initials: M
authors.lastname: Okumura
authors.forename: Masahito
authors.initials: M
authors.lastname: Imanishi
mesh_terms: D000328:Adult; D000450:Aldosterone / Q000097:blood; D001806:Blood Urea Nitrogen; D005260:Female; D005922:Glomerulonephritis, IGA / Q000378:metabolism* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009318:Natriuresis / Q000502:physiology; D009566:Nitrates / Q000097:blood / Q000652:urine; D009569:Nitric Oxide / Q000378:metabolism*; D009573:Nitrites / Q000097:blood / Q000652:urine; D012083:Renin / Q000097:blood; D012084:Renin-Angiotensin System / Q000502:physiology*; D012982:Sodium, Dietary / Q000652:urine*
chemical_list: D009566:Nitrates; D009573:Nitrites; D012982:Sodium, Dietary; D009569:Nitric Oxide; D000450:Aldosterone; D012083:Renin