Natriuresis does not account for urinary concentration inhability in the chronically undernourished rat

Through different concentrations of sodium in the diet, we investigated whether the natriuresis observed inthe DBR rats since weaning resulted from the higher Na + intake or from its lower conservation by thekidney and its effect on the urinary concentration. For this purpose, we used a multicentre diet, locally calledthe regional basic diet (DBR) and 60 male Wistar rats, treated from weaning with: (i) control diet, by theAmerican Institute of Nutrition (AIN); ii) DBR supplemented with low Na + content (0.06%), the DBRgroup; (iii) DBR supplemented with normal Na + content (0.3%), the DBRnorm group; iv) DBRsupplemented with high Na + content (3.12%), the DBRhiper group. The excretion capacity in relation tosodium intake was similar between these two groups (99.01 ± 0.12 vs 99.02 ± 0.17%). Malnutritioncompromised the urinary concentration mechanism