Effects of endothelin-3 on water and sodium excretion during extracellular volume expansion.
The aim of the present study was to elucidate the role of an IV dose of endothelin-3 (ET-3) (5 ng Kg-1 min-1) on mean arterial pressure (MAP), on diuresis and natriuresis in control and in volume expanded anesthetized rats. A systemic infusion of ET-3 in normal rats (Group I) increased MAP and produced a trend of increasing diuresis, without changes in natriuresis. A 10% body weight expansion (Group II) increased diuresis and natriuresis without changes in MAP. The simultaneous infusion of ET-3 and expansion with saline (Group III) resulted in an increase in MAP, an enhanced diuretic response, and a natriuresis of similar magnitude to that observed in Group II. These results suggest that the diuresis produced by a low dose of exogenous ET-3 in control rats, is independent of sodium excretion. Furthermore, the enhanced diuresis caused by ET-3 during expansion is greater than the addition of ET-3 and expansion effects, suggesting that new mechanisms are triggered in order to maintain volume and salt homeostasis in this state.
Majowicz
M P
MP
Cátedras de Biología Celular e Histología, Departmento de Ciencias Biologicas, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires, Argentina. mmajow@huemul.ffyb.uba.ar
Costa
M A
MA
Balaszczuk
A M
AM
Vidal
N A
NA
Bombicino
K A
KA
Arranz
C T
CT
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D048429:Cell Size / Q000502:physiology; D004231:Diuresis / Q000502:physiology; D019334:Endothelin-3 / Q000502:physiology*; D005110:Extracellular Space / Q000378:metabolism*; D008297:Male; D009318:Natriuresis / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012964:Sodium / Q000378:metabolism*; D014867:Water / Q000378:metabolism*
D019334:Endothelin-3; D014867:Water; D012964:Sodium