Abstract
Plasma renin activity (PRA) and aldosterone levels are dependent on daily sodium balance and have been significantly correlated with urinary sodium concentrations and blood pressure in the adult and in newborn infants. Potassium is an important stimulus for aldosterone secretion in the adult but it is not known whether potassium stimulates aldosterone in the newborn. The purpose of this study is to determine the effects of potassium on aldosterone and PRA levels in the newborn lamb. Five newborn lambs 5-10 days of age were infused with KCl 2 mEq/Kg in 20 ml of isotonic saline over 15 min. Blood samples were drawn at 5, 15, 30 and 60 min. after the start of the infusion for measurements of plasma aldosterone and PRA by RIA and serum sodium and potassium by flame photometry. The serum potassium levels increased from a M and SEM baseline of 4.6 ± .005 mEq/L to 6.4 ± 0.4 (p<.05) at 15 min. and 6.4 ± 0.2 (p<.05) at 30 min. decreasing to 5.6 ± 0.3 at 60 min after starting the potassium infusion. Plasma aldosterone levels increased from a (M and SEM; ng/dl) base-line of 5.3 ± 0.4 to 11 ± 1.1 at 15 min. (p<.01), 12.8 ± 2.3 at 30 min. (p<.05) and 19.5 ± 7.2 at 60 min. There were no changes in PRA, Hct, serum Na, or blood pressure during the 60 min. study.
These results show that potassium is capable of stimulating aldosterone in the newborn lamb, while not depressing PRA.
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Siegel, S., Fisher, D. 212 POTASSIUM STIMULATION OF ALDOSTERONE IN THE NEWBORN LAMB. Pediatr Res 12 (Suppl 4), 399 (1978). https://doi.org/10.1203/00006450-197804001-00217
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DOI: https://doi.org/10.1203/00006450-197804001-00217