Cardiovascular Research Advance Access [Accepted Manuscript] published online on November 5, 2007
Cardiovascular Research, doi:10.1093/cvr/cvm059
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Orchidectomy increases the formation of prostanoids and modulates their role in the acetylcholine-induced relaxation in the rat aorta
Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, C/Arzobispo Morcillo 4, 28029 Madrid, Spain
Corresponding author: Dr. Mercedes Ferrer, Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, C/Arzobispo Morcillo 4, 28029 Madrid, Spain; tel.: +34 91 497 3112; fax: +34 91 497 5478; e-mail: mercedes.ferrer{at}uam.es
Aim: This study examines the effect of endogenous male sex hormones on thromboxane A2 (TXA2), prostaglandin (PG) I2, PGF2
and PGE2 release, as well as their role in acetylcholine (ACh)-mediated relaxation in the aorta.
Methods: Aortic segments from orchidectomized and control male Sprague-Dawley rats were used to measure COX-2 protein expression. ACh-induced relaxation of these segments was also determined in the absence and presence of the COX-2 inhibitor NS-398, the TXA2 synthesis inhibitor furegrelate, the PGI2 synthesis inhibitor tranylcypromine (TCP) or the thromboxane-prostanoid (TP) receptor antagonist SQ-29548. Furthermore, TXA2, PGI2, PGF2
and PGE2 release as well as the vasomotor effect of exogenous TXA2, PGI2, PGF2
and PGE2 were measured.
Results: COX-2 expression was increased in aortas from orchidectomized rats. NS-398 did not modify the ACh-induced relaxation in arteries from both control or orchidectomized rats. Neither furegrelate nor TCP modified ACh-induced relaxation in aortas from control animals but, in aortas from orchidectomized rats, they increased or decreased the ACh-induced relaxation, respectively. The TP receptor antagonist, SQ29,548 failed to modify ACh-induced relaxation in aortas from either rat group. Preincubating arteries from orchidectomized rats with TCP plus furegrelate did not modify the decrease in the ACh response induced by TCP alone, but this response was restored by co-incubation of TCP plus SQ29,548. ACh-induced TXA2, PGI2, PGF2
and PGE2 release were increased by orchidectomy. The presence of furegrelate plus TCP increased the ACh-induced PGE2 release more in arteries from orchidectomized than in those from control rats. The contractile responses induced by the TXA2 mimetic U-46619 or by exogenous PGF2
were similar in arteries from control and orchidectomized rats, while those induced by exogenous PGE2 were increased in arteries from orchidectomized rats; the vasodilator response induced by exogenous PGI2 was decreased in arteries from orchidectomized rats.
Conclusions: These data show that endogenous male sex hormone deprivation increases COX-2 expression, the release of TXA2, PGI2, PGF2
and PGE2 and the contractile response induced by exogenous PGE2 and TXA2, while it decreases the relaxation induced by exogenous PGI2. Despite the predominance of vasoconstrictor prostanoids derived from COX-2 in aortas from orchidectomized rats, the ACh-induced relaxation remains increased.
KEYWORDS Male sex hormones; TXA2; PGF2
; PGE2; PGI2; Endothelium; Rat aorta
Time for primary review: 33
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L del Campo, A Sagredo, R Aras-Lopez, G Balfagon, and M Ferrer Orchidectomy increases the formation of non-endothelial thromboxane A2 and modulates its role in the electrical field stimulation-induced response in rat mesenteric artery J. Endocrinol., May 1, 2008; 197(2): 371 - 379. [Abstract] [Full Text] [PDF] |
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