Ammonium chloride metabolic acidosis and the activity of renin-angiotensin-aldosterone system in children.
The present study was undertaken to assess the effects of acute metabolic acidosis on the activity of the renin-angiotensin-aldosterone system in 12 children with a mean age of 8.9 years who underwent NH4Cl loading test. Ammonium chloride was given in a dose of 0.15 g/kg per day for 3 consecutive days to evaluate renal acidification. Prior to and following NH4Cl administration blood acid-base parameters, plasma and urine electrolytes, creatinine and aldosterone concentrations as well as plasma renin activity (PRA), urine flow rate and net H+ excretion were measured. Ammonium chloride administration significantly depressed blood pH (P less than 0.05), bicarbonate (P less than 0.01) and base excess (P less than 0.01) and resulted in a slight, but significant elevation of plasma potassium concentration (P less than 0.05). Furthermore, NH4Cl ingestion induced a marked increase in urine flow rate (P less than 0.01) and urinary sodium, potassium and chloride excretion (P less than 0.01). In response to NH4Cl metabolic acidosis, PRA doubled (4.72 +/- 1.18 vs 8.13 +/- 1.02 ng/ml per hour, P less than or equal to 0.05) and there was a nearly four-fold increase in plasma aldosterone level (0.49 +/- 0.12 vs 1.52 +/- 0.24 ng/ml, P less than 0.01) and in urinary aldosterone excretion (19.2 +/- 4.3 vs 71.8 +/- 13.8 micrograms/day, P less than 0.01). The elevated aldosterone production observed in this study is assumed to be mediated by the combined effect of sodium and water diuresis-related increased PRA, hyperkalaemia and the direct stimulation of adrenal steroidogenesis by metabolic acidosis.
Györke
Z S
ZS
County Children's Hospital, Pécs, Hungary.
Sulyok
E
E
Guignard
J P
JP
D000136:Acid-Base Equilibrium / Q000187:drug effects; D000138:Acidosis / Q000097:blood / Q000378:metabolism* / Q000652:urine; D000293:Adolescent; D000450:Aldosterone / Q000097:blood* / Q000652:urine; D000643:Ammonium Chloride / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D002712:Chlorides / Q000097:blood / Q000652:urine; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D011188:Potassium / Q000097:blood / Q000652:urine; D012083:Renin / Q000097:blood*; D012084:Renin-Angiotensin System / Q000187:drug effects*; D012964:Sodium / Q000097:blood / Q000652:urine
D002712:Chlorides; D000643:Ammonium Chloride; D000450:Aldosterone; D012964:Sodium; D012083:Renin; D011188:Potassium