Testosterone causes direct relaxation of rat thoracic aorta.
Title
Testosterone causes direct relaxation of rat thoracic aorta.
Creator
Costarella C E; Stallone J N; Rutecki G W; Whittier F C
Publisher
The Journal of pharmacology and experimental therapeutics
Date
1996
1996-04
Description
Several recent studies have provided evidence that gonadal steroid hormones can exert acute (nongenomic) effects on both neural and vascular tissues. This study examines the acute effects of testosterone (T) on vascular reactivity of the rat thoracic aorta. Aortic rings from male Sprague-Dawley (SD) rats with (+ENDO) and without (-ENDO) endothelium were prepared for isometric tension recording. In (+ENDO) male aortae precontracted with phenylephrine (PE), T produced dose-dependent relaxation from 25 microM (30.3 +/- 7.1%) to 300 microM (99.4 +/- 0.4%), whereas T vehicle (\textless or = 0.5% ethanol) had no effect. Pretreatment of (+ENDO) aortae with T (50 microM; 10 min) attenuated subsequent contractile responses to PE. Both maximal contraction and sensitivity to PE were reduced by T. Pretreatment of (+ENDO) aortae with both T and N omega-nitro-L-arginine methyl ester (250 microM) reversed in part the attenuating effects of T alone; however, both maximal response and sensitivity to PE were still reduced compared to control rings (without T or N omega-nitro-L-arginine methyl ester). Pretreatment of (-ENDO) aortae with T reduced sensitivity to PE, but had no effect on maximal contraction. T pretreatment (50 microM; 10 min) of both (+ENDO) female SD aortae and (+ENDO) male testicular-feminized rat aortae reduced maximal contraction and sensitivity to PE in both groups to a similar extent as in (+ENDO) male SD aortae. These data suggest that T has a direct vasodilating effect on the rat aorta, which involves endothelium-dependent (enhanced NO release) and -independent mechanisms and is gender- and intracellular androgen receptor-independent.
Subject
Female; Male; Animals; Rats; In Vitro Techniques; Vasodilation/*drug effects; Testosterone/*pharmacology; Phenylephrine/pharmacology; Calcium Channels/drug effects; Dose-Response Relationship; Drug; Sprague-Dawley; Aorta; Endothelium; Thoracic/*drug effects/physiology; Vascular/physiology
Rights
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
Pages
34–39
Issue
1
Volume
277
Citation
Costarella C E; Stallone J N; Rutecki G W; Whittier F C, “Testosterone causes direct relaxation of rat thoracic aorta.,” NEOMED Bibliography Database, accessed April 26, 2024, https://neomed.omeka.net/items/show/5353.