Urocortin 2 inhibits furosemide-induced activation of renin and enhances renal function and diuretic responsiveness in experimental heart failure.
BACKGROUND
Urocortin 2 (Ucn2), a novel peptide with therapeutic potential in heart failure, and diuretics have opposing effects on renal function and the renin-angiotensin-aldosterone system. Because any prospective new treatment is likely to be used in conjunction with standard diuretic therapy, it is necessary to investigate the combined effects of these agents.


RESULTS
Ucn2 and furosemide were administered for 3 hours, both singly and combined, in 7 sheep with pacing-induced heart failure. Compared with time-matched controls, separate Ucn2 and furosemide administration significantly increased urine output (furosemide>Ucn2), urine sodium (furosemide>Ucn2), potassium (furosemide>Ucn2), and creatinine excretion (Ucn2>furosemide) and creatinine clearance (Ucn2>furosemide). Compared with furosemide treatment alone, Ucn2+furosemide produced a further diuresis (P<0.05), natriuresis (P<0.05), and a sustained increase in creatinine excretion (P<0.05) and clearance (P<0.05), without additional potassium elimination. All active treatments reduced mean arterial pressure (Ucn2+furosemide=furosemide>Ucn2), left atrial pressure (Ucn2+furosemide>Ucn2>furosemide), and peripheral resistance (Ucn2+furosemide=Ucn2>furosemide), whereas only Ucn2, singly and in combination with furosemide, increased cardiac output and dP/dt(max). In contrast to the increase in plasma renin activity elicited by furosemide alone, Ucn2 and Ucn2+furosemide markedly reduced plasma renin activity. All active treatments decreased plasma aldosterone (Ucn2+furosemide=Ucn2>furosemide), whereas only Ucn2 and Ucn2+furosemide reduced vasopressin and natriuretic peptide concentrations.


CONCLUSIONS
Ucn2 cotreatment with furosemide enhanced hemodynamic and renal function and diuretic responsiveness (without additional potassium depletion) in experimental heart failure. Furthermore, Ucn2 reversed furosemide-induced increases in plasma renin activity and induced greater decreases in plasma aldosterone and vasopressin. These data indicate that adjunct Ucn2 therapy with diuretics in heart failure is beneficial.
Rademaker
Miriam T
MT
Christchurch Cardioendocrine Research Group, Christchurch School of Medicine, Christchurch, New Zealand. miriam.rademaker@chmeds.ac.nz
Charles
Christopher J
CJ
Nicholls
M Gary
MG
Richards
A Mark
AM
D000450:Aldosterone / Q000097:blood; D000818:Animals; D015415:Biomarkers / Q000097:blood; D002304:Cardiac Pacing, Artificial; D002317:Cardiovascular Agents / Q000008:administration & dosage*; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage*; D003404:Creatinine / Q000097:blood; D004195:Disease Models, Animal; D004232:Diuretics / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D005260:Female; D005665:Furosemide / Q000008:administration & dosage*; D006333:Heart Failure / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology; D006439:Hemodynamics / Q000187:drug effects; D007261:Infusions, Intra-Arterial; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D051379:Mice; D009318:Natriuresis / Q000187:drug effects; D011188:Potassium / Q000097:blood; D012083:Renin / Q000097:blood*; D012084:Renin-Angiotensin System / Q000187:drug effects*; D012756:Sheep; D013997:Time Factors; D014554:Urination / Q000187:drug effects; D054832:Urocortins / Q000008:administration & dosage*; D014667:Vasopressins / Q000097:blood
D015415:Biomarkers; D002317:Cardiovascular Agents; D004232:Diuretics; D054832:Urocortins; C518358:urocortin 2, mouse; D014667:Vasopressins; D000450:Aldosterone; D005665:Furosemide; D003346:Corticotropin-Releasing Hormone; D003404:Creatinine; D012083:Renin; D011188:Potassium