Plasma endothelin and renal endothelin are two distinct systems involved in volume homeostasis.
This study of seven healthy young subjects was designed both to establish whether endothelin-1 (ET-1) is involved in the homeostasis of blood volume and to clarify the relationship between plasma and urinary ET-1. Acute volume expansion (+17%) caused increases in venous blood pressure (+4.4 mmHg) and the plasma concentration of ET-1 (+129%) and a decrease (-99%) in the urinary excretion of ET-1. Volume depletion (-8.5%) provoked an increase in the plasma concentration of ET-1 without altering the urinary excretion of ET-1. Passive elevation of an arm resulting in a local decrease of venous blood pressure (-17 mmHg) elicited an increase of the local formation of ET-1, with a 10-fold increase in the venous-arterial gradient compared with the opposite arm, which lay at the level of the heart. The increased local formation of ET-1 was blunted by volume expansion. The results indicate that 1) plasma ET-1 and urinary ET-1 represent two different endothelin-generating systems, both of which are involved in the regulation of blood volume, and 2) plasma ET-1 appears to be an important mechanism for the long-lasting adaptations of venous wall tension to changes in blood volume.
Serneri
G G
GG
Clinica Medica I, University of Florence, Italy.
Modesti
P A
PA
Cecioni
I
I
Biagini
D
D
Migliorini
A
A
Costoli
A
A
Colella
A
A
Naldoni
A
A
Paoletti
P
P
D000328:Adult; D001132:Arm / Q000098:blood supply / Q000502:physiology; D001810:Blood Volume; D001815:Bloodletting; D002851:Chromatography, High Pressure Liquid; D016232:Endothelins / Q000097:blood / Q000378:metabolism* / Q000652:urine; D005260:Female; D005947:Glucose / Q000494:pharmacology; D006706:Homeostasis; D006801:Humans; D007275:Injections, Intravenous; D007668:Kidney / Q000378:metabolism*; D008297:Male; D010952:Plasma Substitutes / Q000494:pharmacology; D011187:Posture
D016232:Endothelins; D010952:Plasma Substitutes; D005947:Glucose