Aims: To investigate the haemodynamic, hormonal, and renal effects of peripheral urocortin 3 (Ucn3) administration for the first time in either normal health or heart failure (HF).
Methods and results: Eight sheep received incremental intravenous boli of Ucn3 (10, 50, and 100 microg at 2-h intervals) before (normal) and during pacing-induced HF. Compared with controls, Ucn3 induced immediate, dose-dependent increases in cardiac output (normal 4.21+/-0.23 vs. 5.65+/-0.32 L/min, P<0.001; HF 2.20+/-0.14 vs. 4.43+/-0.31 L/min, P < 0.001) and decreases in peripheral resistance (normal 20.8+/-1.0 vs. 16.2+/-0.8 mmHg/L/min, P < 0.01; HF 34.4+/-1.7 vs. 16.2+/-0.5 mmHg/L/min, P < 0.001) and left atrial pressure (normal 4.5+/-0.3 vs. 0.6+/-0.2 mmHg, P < 0.001; HF 23.0+/-0.6 vs. 5.8+/-1.9 mmHg/L/min, P < 0.001). Arterial pressure was minimally elevated in normals (P < 0.001) and reduced in HF (P < 0.05). In HF only, Ucn3 decreased plasma vasopressin (3.33+/-0.36 vs. 1.73+/-0.21 pmol/L, P < 0.05), endothelin-1 (3.56+/-0.28 vs. 2.64+/-0.24 pmol/L, P < 0.001), renin (2.74+/-1.17 vs. 1.04+/-0.22 nmol/L/h, P < 0.001), aldosterone (1494+/-400 vs. 726+/-168 pmol/L, P < 0.05), and epinephrine (1608+/-278 vs. 1039+/-75 pmol/L, P < 0.05), and increased urine output (P < 0.05), sodium excretion (P < 0.01), and creatinine clearance (P < 0.05).
Conclusion: Ucn3 has significant cardiovascular effects in normal and HF sheep, supporting a role for this peptide in circulatory regulation. In HF, more prominent haemodynamic changes were associated with beneficial endocrine and renal effects, suggesting Ucn3 has therapeutic potential in this disease.