Abstract
Simultaneous measurement of plasma renin activity /PRA/ plasma aldosterone concentration /PA/ and urinary aldosterone excretion /UAE/ of 7 healthy premature infants with mean birth weight of 1580g /range:1160-1850g/ and mean gestational age of 31 weeks /range :30-32 weeks/ was made using RIA methods along with determination of Na and K balance weekly up to 6-th week of life.
Due to the increased urinary Na loss negative Na balance developed in the first two weeks followed by positive balance thereafter. PRA,PA and UAE increased tremendously from the initially high values of 18.2±4.1 ng/ml/hr,1.7±0.5ng/ml and 3.2±0.9 μg/day /mean and SEM/ to their maximum of 78.6±18.1 μg/ml/hr /p < 0.01/, 6.8±2.7 ng/ml /p < 0.05/ and 25.1±8.1 μg/day /p < 0.01/ in the third week, respectively.Later on, gradual declines occurred,however,PRA,PA and UAE remained highly elevated even at the 6-th week with values of 45.5±15 μg/ml/ /hr, 1.6±0.5 ng/ml and 15.1±4.6 μg/day,respectively.
It is suggested that late hyponatraemia of premature infants is due to tubular unresponsiveness to aldosterone and not to inadequate response of RAAS to stimulation.
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Sulyok, E., Varga, F., Németh, M. et al. POSTNATAL DEVELOPMENT OF RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM /RAAS/ IN RELATION TO ELECTROLYTE BALANCE IN PREMATURE INFANTS. Pediatr Res 13, 75 (1979). https://doi.org/10.1203/00006450-197901000-00038
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DOI: https://doi.org/10.1203/00006450-197901000-00038
