Furosemide effect on isolated perfused tubules.

BURG, MI., L. STONER, J. CARDINAL, AND N. GREEN. Furosemide effect on isolated perfused tubules. Am. J. Physiol. 225(l): 119-124. 1973 .-Proximal convoluted tubules, thick ascending limbs of Henle’s loop, and cortical collecting tubules were dissected from rabbit kidneys, and perfused in vitro. The effect of the diuretic agent furosemide on electrolyte transport and electrical potential difference (PD) in these segments was determined. Furosemide in the lumen (lo-” to lOA M) inhibited active Cl transport in the thick ascending limbs of Henle’s loop with resultant decrease in net NaCl absorption and electrical PD. Concentrations of furosemide as high as 10 -4 M in the bath had little effect. Furosemide at low4 M also had no definite effect on proximal convoluted tubules and cortical collecting tubules whether placed in the bath and/or the lumen. We conclude that the principal renal action of this drug is to inhibit active Cl transport in the thick ascending limb of Henle’s loop.