Oral contraceptive-induced high blood pressure is prevented by renin-angiotensin suppression in female rats but not by sympathetic nervous system blockade.
The use of oral contraceptive (OC) steroids is associated with high blood pressure, although mechanisms responsible are still unclear. This study sought to investigate the possible roles that renin-angiotensin system (RAS) and sympathetic nervous system (SNS) may play in the development of OC-induced hypertension. Administration of OC led to significant increases in blood pressure, heart weight and significant decrease in urinary output in OC-treated and OC+clonidine-treated groups but not in OC+captopril-treated group. The pressor response to angiostensin II was significantly greater in the OC-treated rats than in the control rats. However, the pressor responses induced by norepinephrine were not significantly affected by OC administration. The results of the present study demonstrate that OC-induced high blood pressure is associated with cardiac hypertrophy, enhanced pressor response to angiotensin II and preserved pressor response to sympathetic activation. The study also suggests that the development of the OC-induced hypertension and cardiac hypertrophy is mediated by RAS, but not by SNS.
Olatunji
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LA
Department of Physiology, College of Health Sciences, University of Ilorin, P.M.B. 1515, Ilorin, 240001, Nigeria. tunjilaw04@yahoo.com
Soladoye
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AO
D000804:Angiotensin II / Q000378:metabolism; D000818:Animals; D001794:Blood Pressure; D003000:Clonidine / Q000627:therapeutic use; D003276:Contraceptives, Oral / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006973:Hypertension / Q000209:etiology*; D008954:Models, Biological; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012084:Renin-Angiotensin System; D013564:Sympathetic Nervous System / Q000187:drug effects*; D016896:Treatment Outcome
D003276:Contraceptives, Oral; D000804:Angiotensin II; D003000:Clonidine; D009638:Norepinephrine