title: Acute cardiovascular and hormonal effects of GH and hexarelin, a synthetic GH-releasing peptide, in humans.
abstract: 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.
authors.affiliation: Dipartimento di Medicina Interna, University of Torino, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Bisi
authors.forename: V
authors.initials: V
authors.lastname: Podio
authors.forename: M R
authors.initials: MR
authors.lastname: Valetto
authors.forename: F
authors.initials: F
authors.lastname: Broglio
authors.forename: G
authors.initials: G
authors.lastname: Bertuccio
authors.forename: G
authors.initials: G
authors.lastname: Del Rio
authors.forename: E
authors.initials: E
authors.lastname: Arvat
authors.forename: M F
authors.initials: MF
authors.lastname: Boghen
authors.forename: R
authors.initials: R
authors.lastname: Deghenghi
authors.forename: G
authors.initials: G
authors.lastname: Muccioli
authors.forename: H
authors.initials: H
authors.lastname: Ong
authors.forename: E
authors.initials: E
authors.lastname: Ghigo
mesh_terms: 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
chemical_list: D009842:Oligopeptides; C086184:hexarelin; D019382:Human Growth Hormone; D000450:Aldosterone; D006854:Hydrocortisone; D009638:Norepinephrine; D004837:Epinephrine