Endothelin antiserum decreases volume-stimulated and basal plasma concentration of atrial natriuretic peptide.
BACKGROUND
Endothelin-1 (ET-1) is the most powerful factor known to release atrial natriuretic peptide (ANP) in vivo and in cultured cardiac myocytes or preparations of atrium. We tested the role of endogenous ET-1 in the regulation of ANP release by passive immunization in anesthetized rats.


RESULTS
Intravenous injection of antiserum against ET-1 was shown to decrease basal and volume-stimulated plasma concentrations of ANP, whereas control serum was without effect. Antiserum generated in rabbits cross-reacted 100% with endothelin-2 and -3. In pentobarbital-anesthetized Wistar rats treated with ET-1 antiserum, plasma ANP concentration measured by radioimmunoassay was reduced by 37% from starting level after 10 minutes and by 30% after 60 minutes. Control rat serum had no effect on plasma ANP. Rapid intravenous infusion of 8 mL of 0.9% NaCl caused a sixfold increase of plasma ANP concentration in control rats but only twofold in rats pretreated with ET-1 antiserum (P < .01). This effect of ET-1 antiserum was dose dependent. ET-1 antiserum changed neither blood pressure nor heart rate significantly in anesthetized rats. Pretreatment with ET-1 antiserum did not affect the initial hypotensive response to intravenous ET-1 0.5 nmol/kg but significantly attenuated the subsequent hypertensive response to endothelin.


CONCLUSIONS
Endothelin may be a physiological modulator of both basal and stimulated ANP release.
Fyhrquist
F
F
Unit of Clinical Physiology, Minerva Institute for Medical Research, Helsinki, Finland.
Sirviö
M L
ML
Helin
K
K
Saijonmaa
O
O
Metsärinne
K
K
Paakkari
I
I
Järvinen
A
A
Tikkanen
I
I
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000097:blood / Q000378:metabolism*; D001794:Blood Pressure / Q000502:physiology; D016232:Endothelins / Q000276:immunology / Q000502:physiology*; D007106:Immune Sera / Q000494:pharmacology*; D007116:Immunization, Passive; D008297:Male; D011817:Rabbits; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar; D012965:Sodium Chloride
D016232:Endothelins; D007106:Immune Sera; D012965:Sodium Chloride; D009320:Atrial Natriuretic Factor