assuming that amiloride acts by inhibiting sodium reabsorption and potassium secretion in the late distal and cortical collecting tubules , these results support the conclusion that in these regions of the nephron of the new-born dog ( a ) a greater fraction of the filtered sodium is reabsorbed than in the adult and ( b ) increased fractional sodium reabsorption is responsible , in part , for the attenuated natriuretic response to saline expansion .
C0002502
amiloride
C0032821
potassium