Effects of endothelin on renal hemodynamics and tubuloglomerular feedback.
The effect of endothelin (ET)-1 infusion on renal hemodynamics and the tubuloglomerular feedback (TGF) mechanism was examined in rats. ET-1 reduced early proximal flow rate (EPFR) measured in the absence of distal flow from 28 +/- 1 to 23 +/- 1 nl/min at a subpressor dose (100 pmol.100 g body wt-1.h-1 iv) and from 27 +/- 2 to 19 +/- 2 nl/min at a pressor dose (200 pmol.100 g body wt-1.h-1). Reductions of EPFR induced by loop perfusion at 40 nl/min were 11 +/- 1 and 12 +/- 1 nl/min at the subpressor and pressor doses and were not different from controls. The stop-flow pressure response to loop perfusion was not altered by the pressor dose of ET-1. The subpressor dose of ET-1 increased renal vascular resistance (RVR) by 40% but left glomerular filtration rate (GFR) and urinary excretion of sodium (UNaV) unaltered. The pressor dose of ET-1 not only increased RVR by 140% and decreased GFR and renal plasma flow by 37 and 52%, but it increased UNaV proportional to the rise in blood pressure (r = 0.724, P less than 0.01). ET-1 is a potent renal vasoconstrictor and induces pressure natriuresis. ET-1 increases both pre- and postglomerular resistances but does not affect TGF response.
Takabatake
T
T
First Department of Internal Medicine, School of Medicine, Kanazawa University, Japan.
Ise
T
T
Ohta
K
K
Kobayashi
K
K
D000818:Animals; D016232:Endothelins / Q000493:pharmacokinetics / Q000494:pharmacology*; D005246:Feedback; D006439:Hemodynamics / Q000187:drug effects; D007668:Kidney / Q000378:metabolism; D007678:Kidney Glomerulus / Q000187:drug effects* / Q000502:physiology; D007684:Kidney Tubules / Q000187:drug effects* / Q000502:physiology; D007687:Kidney Tubules, Proximal / Q000502:physiology; D008297:Male; D010477:Perfusion; D011312:Pressure; D051381:Rats; D011919:Rats, Inbred Strains; D012079:Renal Circulation / Q000187:drug effects*
D016232:Endothelins