ON MODE OF ACTION OF DIURETICS ACTION OF FUROSEMIDE ON RENAL OXYGEN CONSUMPTION

Urine volume, renal blood flow, glomerular filtration rate, sodium reabsorption (TNa) and oxygen consumption (VO2) have been investigated in anesthetized dogs in control experiments and after injection of 5 mg/kg furosemide. After furosemide the urine volume amounted to more than 20 ml/min × 100 g renal weight, the renal blood flow averaged 128% of the control value, the GFR was constant or slightly decreased. The tubular Na-reabsorption was depressed from 8.8 to 5.6 mEq/min × 100 g that is, from 95 to 70% of the filtered load. The renal oxygen consumption did not change, since the renal a-v-difference of oxygen was decreased by the same relative amount, as the renal blood flow was enhanced. The correlation between TNa and VO2 was significant in controls and after furosemide. The basal VO2 was augmented from 0.07 to 0.1 mM/min × 100 g after furosemide while the ratio TNa/VO2 was lowered significantly. The results are compatible with the hypothesis that furosemide does not primarily inhibit the active transport but depresses the net reabsorption of Na by influencing the cell membrane permeability. © 1969 Springer-Verlag.