title: Role of endothelium in the vasodilating effect of progestins and androgens on the rat thoracic aorta.
abstract: 1. In the rat thoracic aorta, contractions induced by noradrenaline were inhibited by the steroids progesterone, pregnanolone, testosterone and 5 alpha- and 5 beta-dihydrotestosterone. 2. Removal of endothelium did not prevent relaxation to the steroids, suggesting that the vasodilating effect of steroids occurred on the smooth muscle cells. 3. gamma-Aminobutyric acid (GABA) did not modify noradrenaline-induced contraction. Thus, the vasodilation elicited by steroids is not apparently mediated by GABA receptors. 4. On the basis that noradrenaline opens receptor-operated calcium channels to induce contraction, we suggest that relaxation by steroids involves a blockade of this type of channels.
authors: Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City.
authors: M
authors: M
authors: Perusquía
authors: R
authors: R
authors: Hernández
authors: M A
authors: MA
authors: Morales
authors: M G
authors: MG
authors: Campos
authors: C M
authors: CM
authors: Villalón
mesh_terms: D000728:Androgens / Q000494:pharmacology*; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000502:physiology; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D011372:Progestins / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D014662:Vasoconstrictor Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
chemical_list: D000728:Androgens; D011372:Progestins; D014662:Vasoconstrictor Agents; D005680:gamma-Aminobutyric Acid; D009638:Norepinephrine