Effect of diuretics on the tubuloglomerular feedback response.
To study the influence of diuretics on the tubuloglomerular feedback mechanism, early proximal stop-flow pressure (SFP) was measured during loop exposure to different drug concentrations. SFP was recorded continuously during arrested flow and at a perfusion rate of 50 nL/min. The perfusate consisted of isotonic saline, to which varying amounts of furosemide. bumetanide, piretanide, or hydrochlorothiazide were added to obtain final concentrations between 10(-6) and 10(-4)M. The loop diuretics furosemide, bumetanide, and piretanide showed inhibition: an inverse log-linear relation between the luminal concentration and the respective feedback response. No differences between the dose-response curves of furosemide, bumetanide, or piretanide could be demonstrated. The effective concentration range was between 10(-6) and 10(-4)M, the mean effective dose (ED50) was close to 10(-5)M for each of them. In contrast, hydrochlorothiazide did not alter the feedback response. The effect of loop diuretics was rapidly and repeatedly reversible.
D000818:Animals; D001835:Body Weight; D002034:Bumetanide / Q000494:pharmacology; D004232:Diuretics / Q000494:pharmacology*; D005246:Feedback; D005665:Furosemide / Q000494:pharmacology; D006852:Hydrochlorothiazide / Q000494:pharmacology; D007678:Kidney Glomerulus / Q000187:drug effects* / Q000502:physiology; D007684:Kidney Tubules / Q000187:drug effects* / Q000502:physiology; D008086:Lissamine Green Dyes; D008297:Male; D009929:Organ Size; D051381:Rats; D011919:Rats, Inbred Strains; D013449:Sulfonamides / Q000494:pharmacology
D004232:Diuretics; D008086:Lissamine Green Dyes; D013449:Sulfonamides; D006852:Hydrochlorothiazide; D002034:Bumetanide; D005665:Furosemide; C024537:green 5; C015451:piretanide