[A study of urinary immunoglobulins and electrolyte excretion after lordosis].
We described a transient low or non-selective proteinuria after forced lordosis as a characteristic of orthostatic proteinuria and the heteroporous theory and sieving function theory which might explain the mechanism of orthostatic proteinuria. The angiogenic action of the renin-angiotensin system played an important part in these theories. Angiotensin II was recognized as the key regulator of renal sodium excretion, because it reduced the urinary Na/K ratio. Since the purpose of this study is to investigate the influence of the renin-angiotensin system on the mechanism of orthostatic proteinuria, proteins and electrolytes in the urine were examined before and after lordosis in 9 healthy children (Group A) and in 6 children with orthostatic proteinuria (Group B). The urinary ratio of protein/creatinine (P/cre) in Group B was already significantly higher than that in Group A before lordosis and significantly increased after lordosis, while P/cre in group A did not increase after lordosis. The urinary Na/K ratio (Na/K) in Group B was already significantly lower than that in Group A before lordosis, and after forced lordosis, Na/K in Group A decrease with no difference between both groups observed. It is suggested that a significant increase on P/cre after lordosis was obtained only in Group A, whereas in both groups the renal vein may be compressed by forced lordosis and as a result angiotensin II may be stimulated. There might be a difference of the responsibility to angiotensin II in glomerular mesangium contraction between both groups.
Mihata
M
M
Department of Pediatrics, Hyogo College of Medicine, Japan.
Tanizawa
T
T
Tomimoto
Y
Y
Nishioka
M
M
Kawaguchi
M
M
Hatori
M
M
Wada
H
H
D000293:Adolescent; D000328:Adult; D002648:Child; D003404:Creatinine / Q000652:urine; D004573:Electrolytes / Q000652:urine*; D006801:Humans; D007136:Immunoglobulins / Q000652:urine*; D011187:Posture; D011507:Proteinuria / Q000209:etiology* / Q000378:metabolism; D012084:Renin-Angiotensin System
D004573:Electrolytes; D007136:Immunoglobulins; D003404:Creatinine