Acute cardiovascular and hormonal effects of GH and hexarelin, a synthetic GH-releasing peptide, in humans.
Reduced cardiac mass and performances are present in GH deficiency and are counteracted by rhGH replacement. GH and IGF-I possess specific myocardial receptors and have been reported able to exert an acute inotropic effect. Synthetic GH secretagogues (GHS) possess specific pituitary and hypothalamic but even myocardial receptors. In 7 male volunteers, we studied cardiac performance by radionuclide angiocardiography after iv administration of rhGH or hexarelin (HEX), a peptidyl GHS. The administration of rhGH or HEX increased circulating GH levels to the same extent (AUC: 1594.6+/-88.1 vs 1739.3+/-262.2 microg/l/min for 90 min) while aldosterone and catecholamine levels did not change; HEX, but not rhGH, significantly increased cortisol levels. Left ventricular ejection fraction (LVEF), mean blood pressure (MBP) and heart rate (HR) were unaffected by rhGH (62.4+/-2.1 vs 62.1+/-2.3%, 90.6+/-3.4 vs 92.0+/-2.5 mm Hg, 62.3+/-1.8 vs 66.7+/-2.7 bpm). HEX increased LVEF (70.7+/-3.0 vs 64.0+/-1.5%, p<0.03) without significant changes in MBP and HR (92.8+/-4.7 vs 92.4+/-3.2 mm Hg, 63.1+/-2.1 vs 67.0+/-2.9 bpm). LVEF significantly raised at 15 min, peaked at 30 min and lasted up to 60 min after HEX. These findings suggest that in man, the acute administration of Hexarelin exerts a short-lasting, positive inotropic effect. This effect seems GH-independent and might be mediated by specific GHS myocardial receptors.
Bisi
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G
Dipartimento di Medicina Interna, University of Torino, Italy.
Podio
V
V
Valetto
M R
MR
Broglio
F
F
Bertuccio
G
G
Del Rio
G
G
Arvat
E
E
Boghen
M F
MF
Deghenghi
R
R
Muccioli
G
G
Ong
H
H
Ghigo
E
E
D000328:Adult; D000450:Aldosterone / Q000097:blood; D000790:Angiocardiography; D001794:Blood Pressure / Q000187:drug effects; D002319:Cardiovascular System / Q000000981:diagnostic imaging / Q000187:drug effects*; D004837:Epinephrine / Q000097:blood; D005483:Flushing / Q000139:chemically induced; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D019382:Human Growth Hormone / Q000008:administration & dosage / Q000009:adverse effects / Q000097:blood / Q000494:pharmacology*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D009638:Norepinephrine / Q000097:blood; D009842:Oligopeptides / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D013997:Time Factors
D009842:Oligopeptides; C086184:hexarelin; D019382:Human Growth Hormone; D000450:Aldosterone; D006854:Hydrocortisone; D009638:Norepinephrine; D004837:Epinephrine