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

Rossoni, G., Locatelli, V., De Gennaro Colonna, V., Torsello, A., Schweiger, F., Boghen, M., et al. (1999). Growth hormone and hexarelin prevent endothelial vasodilator dysfunction in aortic rings of the hypophysectomized rat. JOURNAL OF CARDIOVASCULAR PHARMACOLOGY, 34(3), 454-460 [10.1097/00005344-199909000-00021].

Growth hormone and hexarelin prevent endothelial vasodilator dysfunction in aortic rings of the hypophysectomized rat

LOCATELLI, VITTORIO;TORSELLO, ANTONIO BIAGIO;
1999

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
Articolo in rivista - Articolo scientifico
Animals; Human Growth Hormone; Aorta; Humans; Endothelin-1; Enzyme Inhibitors; Homeostasis; Protective Agents; Endothelium, Vascular; Rats; Body Weight; Rats, Sprague-Dawley; 6-Ketoprostaglandin F1 alpha; Vasodilation; Hypophysectomy; omega-N-Methylarginine; Acetylcholine; Oligopeptides; Male
English
1999
34
3
454
460
none
Rossoni, G., Locatelli, V., De Gennaro Colonna, V., Torsello, A., Schweiger, F., Boghen, M., et al. (1999). Growth hormone and hexarelin prevent endothelial vasodilator dysfunction in aortic rings of the hypophysectomized rat. JOURNAL OF CARDIOVASCULAR PHARMACOLOGY, 34(3), 454-460 [10.1097/00005344-199909000-00021].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/38273
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