Growth hormone and hexarelin prevent endothelial vasodilator dysfunction in aortic rings of the hypophysectomized rat
Articolo
Data di Pubblicazione:
1999
Citazione:
Growth hormone and hexarelin prevent endothelial vasodilator dysfunction in aortic rings of the hypophysectomized rat / G. Rossoni, V. Locatelli, V. De Gennaro Colonna, A. Torsello, F. Schweiger, M. Boghen, M. Nilsson, M. Bernareggi, E.E. Müller, F. Berti. - In: JOURNAL OF CARDIOVASCULAR PHARMACOLOGY. - ISSN 0160-2446. - 34:3(1999 Sep), pp. 454-460. [10.1097/00005344-199909000-00021]
Abstract:
The endothelial vasodilation mechanism(s) has been investigated in aortic rings of hypophysectomized male rats as well as hypophysectomized rats treated for 7 days with growth hormone (GH, 400 microg/kg, s.c.) or hexarelin (80 microg/kg, s.c.). Tissue preparations from intact animals were taken as controls. The results obtained indicate that the release of 6-keto-prostaglandin F1alpha (6-keto-PGF1alpha) from aortic rings of hypophysectomized rats was markedly reduced (51%; p<0.01) as compared with that of control preparations; the peak response to cumulative concentration of endothelin-1 (ET-1, from 10(-11) to 10(-5) M) was increased 2.4-fold (p<0.01) versus controls; the relaxant activity of acetylcholine (ACh, from 10(-10) to 10(-4) M) in norepinephrine-precontracted aortic rings was reduced by 39.5+/-4.4%. Pretreatment of hypophysectomized rats with GH or hexarelin markedly antagonized the hyperresponsiveness of the aortic tissue to ET-1 and allowed a consistent recovery of both the relaxant activity of ACh and the generation of 6-keto-PGF1alpha. Collectively these findings support the concept that dysfunction of vascular endothelial cells may be induced by a defective GH function. Because a replacement regimen of GH restored the somatotropic function and increased plasma insulin-like growth factor-I (IGF-I) concentrations in the hypophysectomized rats, it is suggested that IGF-I may have protected the vascular endothelium acting as a biologic mediator of GH action. In contrast to GH, hexarelin replacement neither increased body weight nor affected the plasma concentrations of IGF-I, indicating that its beneficial action on vascular endothelium was divorced from that on somatotropic function and was likely due to activation of specific endothelial receptors
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Acetylcholine; Aortic rings; Endothelin-1; Growth hormone; Hexarelin; Hypophysectomy; Vascular endothelium dysfunction
Elenco autori:
G. Rossoni, V. Locatelli, V. De Gennaro Colonna, A. Torsello, F. Schweiger, M. Boghen, M. Nilsson, M. Bernareggi, E.E. Müller, F. Berti
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