Cardiac effects of hexarelin in hypopituitary adults.
Growth hormone (GH)-releasing peptides possess specific pituitary, hypothalamic, and myocardial receptors. Seven adult male patients with GH deficiency (GHD) (age, mean+/-S.E.M.: 42.0+/-4.0 year) were studied by equilibrium radionuclide angiocardiography after i.v. administration of hexarelin, a peptide GH secretagogue. Data for these patients were compared with those for nine adult male controls (37.0+/-2.7 year). The GH response to hexarelin was negligible in patients with GHD compared to control subjects (CS) (peak: 1.9+/-0.9 vs. 45.7+/-3.6 microg/l, P<0.001). Basal left ventricular ejection fraction (LVEF) in patients with GHD was lower than that in CS (50+/-1% vs. 63+/-2%, P<0.001). Hexarelin administration increased LVEF both in patients with GHD and in CS (peak: 57+/-2 vs. 70+/-2, respectively, P<0.05 vs. baseline) without changing catecholamine levels, mean blood pressure (MBP), or cardiac output in either group. In conclusion, the acute administration of hexarelin exerts a short-lasting positive inotropic effect in humans, probably GH-independent and mediated by specific myocardial receptors for GH secretagogues.
Bisi
G
G
Division of Nuclear Medicine and Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Turin, Ospedale Molinette, C.so Dogliotti 14, 10126 Turin, Italy. bisi@molinette.unito.it
Podio
V
V
Valetto
M R
MR
Broglio
F
F
Bertuccio
G
G
Aimaretti
G
G
Pelosi
E
E
Del Rio
G
G
Muccioli
G
G
Ong
H
H
Boghen
M F
MF
Deghenghi
R
R
Ghigo
E
E
D000328:Adult; D005483:Flushing / Q000139:chemically induced; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology; D006439:Hemodynamics / Q000187:drug effects; D019382:Human Growth Hormone / Q000097:blood / Q000172:deficiency / Q000187:drug effects; D006801:Humans; D007018:Hypopituitarism / Q000000981:diagnostic imaging / Q000503:physiopathology*; D007334:Insulin-Like Growth Factor I / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009842:Oligopeptides / Q000009:adverse effects / Q000494:pharmacology*; D011875:Radionuclide Angiography
D009842:Oligopeptides; C086184:hexarelin; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I