Urinary Excretion of Endogenous Ouabain-Like Substance in Furosemide-Treated Neonates: Its Relation to Renal Excretory Pattern and Endocrine Factors

Abstract

The present study was undertaken to define the possible role of endogenous ouabain-like substance (EOLS) in controlling renal excretory pattern, in mediating the renal responses to furosemide and in inducing endocrine reactions in furosemide-treated neonates. Ten newborn infants with mean birthweight of 2,752 g and mean gestational age of 37.1 weeks were given furosemide in a dose of 1 mg/kg. Prior to and following furosemide therapy, urine was collected for a period of 12 h and analyzed for creatinine, osmolality, sodium and potassium, as well as for EOLS, arginine vasopressin (AVP), aldosterone and endothelin-1 (ET-1). In response to furosemide administration, urine flow rate and urinary osmolar, sodium and potassium excretion increased significantly, whereas creatinine excretion remained unchanged. Furthermore, following furosemide therapy, urinary excretion of EOLS (148.7 ± 70.8 vs. 200.1 ± 98.1 pg/kg/h) and AVP (19.5 ± 5.4 vs. 27.8 ± 7.8 pg/kg/h) tended to increase, whereas ET-1 (36.0 ± 5.6 vs. 61.4 ± 8.7fmol/kg/h, p < 0.01) and aldosterone (507 ± 120 vs. 751 ± 203 ng/kg/h, p < 0.05) increased significantly. Prior to furosemide, urinary EOLS excretion was found to correlate positively with diuresis (r = 0.80, p < 0.01), sodium (r = 0.91, p < 0.001), creatinine (r = 0.75, p < 0.001), osmolar (r = 0.96, p < 0.001), ET-1 (r = 0.90, p < 0.001) and AVP (r = 0.92, p < 0.001) excretion. After furosemide, urinary EOLS excretion significantly correlated only with diuresis (r = 0.69, p < 0.05), ET-1 (r = 0.77, p < 0.01) and AVP (r = 0.92, p < 0.001). Urinary EOLS proved to be independent of aldosterone excretion irrespective of furosemide administration. It is concluded that urinary EOLS excretion is closely related to neonatal renal excretory pattern and it may have a role in controlling diuresis and natriuresis. The renal response to furosemide appears to be independent of EOLS, although interdependent endocrine reactions can be induced by furosemide which may modulate the production rate and urinary excretion of EOLS.

The Na+/Ca2+ exchanger: A possible link between oxidative stress and endogenous ouabain in hypertension

“…Ouabain like substance is also found in infants [132]. In the urine of premature infants supplemented with NaCl and in infants treated with furosemide, the level of ouabain excreted in the urine is reduced significantly [133,134]. Ouabain and ouabain-like substances are also found in the blood of hypertensive pregnant mothers and their infants [135][136][137].…”

Συγκριτική Εκτίμηση Της Νεφρικής Λειτουργίας Σε Πρόωρα Νεογνά Κατάλληλου Βάρους Και Πρόωρα Λιποβαρή Νεογνά Καθώς Και Η Επίδραση Των Αμινογλυκοσιδών Στην Ωρίμανση Της Σπειραματικής Και Σωληναριακής Λειτουργίας

“…Στη νεφρική ρύθμιση του Na συμμετέχουν ορισμένοι ορμονικοί παράγοντες στους οποίους περιλαμβάνονται: το σύστημα ρενίνης -αγγειοτενσίνης -αλδοστερόνης, η ντοπαμίνη, ο κολπικός νατριουρητικός παράγοντας, η ενδοθηλίνη-1, το μονοξείδιο του αζώτου (ΝΟ) και η ενδογενής ουαμπαϊνη. Μελέτες έχουν δείξει ότι η δράση των παραγόντων αυτών στον ανώριμο νεφρό διαφέρει από τη δράση του Na στο νεφρό του ενήλικα 99,100 .…”