Abstract
Net sodium absorption in the jejunum was determined in 20, 40 and 80 day-old rats. The jejunum was perfused in vivo (10 ml/100 g BW/h) with an isotonic electrolyte solution containing C14 PEG 4000 (MW range 2500-6000) 5 g/l, which was used as a marker of water absorption. In 20 d controls (C) there was a significantly higher net sodium absorption (48.3±2.45 /uEq/min/g dry weight) than in 40 d (27.3±2.57) p<0.01 and in 80 d (32.8±2.53) p<0.01. HS was accomplished by replacing the drinking water with isotonic saline for 4 days prior to study. In 20 d HS rats net sodium absorption was significantly decreased compared to 20 d C (34.6±0.9) p<0.01, but there were no differences compared to controls in 40 d HS (33.1±2.79) or in 80 d HS (34.1±2.91). In the kidney locally produced dopamine DA will contribute to the natriuretic response to salt load (Kidney Int 1987, 31: 258). When 20 d HS were fed benserazide, an inhibitor of L-dopa decarboxylase, prior to study, the net sodium absorption significantly increased compared to untreated 20 d HS to the same magnitude as in controls (49.9±1.81) p<0.01. There was no effect of benserazide in 40 d HS and 80 d HS.
Conclusion: Basal jejunal Na uptake is higher and changes in jejunal Na uptake play a more important role for the adaptation to HS intake in young than in adult rats. Dopamine contributes to the response of the young jejunum to HS.
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Finkel, Y., Bertorello, A. & Aperia, A. 52 INTESTINAL Na UPTAKE DECREASES AFTER HIGH SALT DIE (HS) IN YOUNG BUT NOT IN ADULT RAT. Pediatr Res 24, 413 (1988). https://doi.org/10.1203/00006450-198809000-00075
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DOI: https://doi.org/10.1203/00006450-198809000-00075