Pressor Effects of Portal Venous Oleate Infusion: A Proposed Mechanism for Obesity Hypertension

• Published in: Hypertension (Dallas, Tex. 1979) Vol. 26; no. 1; pp. 193 - 198
• Main Authors: Grekin, Roger J, Vollmer, Alan P, Sider, Richard S
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Heart Association, Inc 01.07.1995; Hagerstown, MD Lippincott
• Subjects: Analysis of Variance; Animals; Antihypertensive Agents - administration & dosage; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; Blood Glucose - analysis; Blood Pressure - drug effects; Caprylates - administration & dosage; Cardiology. Vascular system; Corticosterone - blood; Epinephrine - blood; Experimental diseases; Fatty Acids - blood; Femoral Vein; Heart Rate - drug effects; Hypertension - blood; Hypertension - etiology; Infusions, Intravenous; Insulin - blood; Liver Function Tests; Male; Medical sciences; Norepinephrine - blood; Obesity - blood; Obesity - complications; Oleic Acid; Oleic Acids - administration & dosage; Oleic Acids - pharmacology; Portal Vein; Radioimmunoassay; Rats; Rats, Sprague-Dawley; Renin - blood; Time Factors; Triglycerides - blood; Hypertension; Obesity; Rat; Rodentia; Nutrition disorder; Cardiovascular disease; Catecholamine; Vertebrata; Experimental disease; Mammalia; Association; Arterial pressure; Norepinephrine; Portal vein; Nutritional status
• ISSN: 0194-911X; 1524-4563
• DOI: 10.1161/01.HYP.26.1.193

Increased visceral fat accumulation is a strong predictor of arterial hypertension. In this study, we explored the hypothesis that increased hepatic portal venous free fatty acid delivery results in increased blood pressure. Such an effect might explain the link between visceral obesity and hypertension. In nine conscious, instrumented rats, we studied the effects of 1-hour infusions of sodium oleate solution into the portal and femoral veins and infusions of sodium caprylate solution into the portal vein on 3 separate days. Basal blood pressure was not significantly different on the 3 study days. Mean arterial pressure increased 29 plus/minus 4 mm Hg during portal oleate infusion and 13 plus/minus 2 mm Hg during femoral oleate infusion (both significant increases over basal, P < .001). Mean arterial pressure did not change during portal caprylate infusion. The increase during portal oleate infusion was greater than that during femoral oleate infusion (P = .028). Heart rate rose during all three infusions; the increase was greatest during portal oleate infusion (334 plus/minus 4 to 412 plus/minus 2 beats per minute). During portal venous oleate infusion in five rats, plasma norepinephrine rose from 2.17 plus/minus 0.34 to 3.58 plus/minus 0.50 nmol/L, epinephrine rose from 0.79 plus/minus 0.28 to 1.84 plus/minus 0.44 nmol/L, and corticosterone rose from 147 plus/minus 55 to 1130 plus/minus 289 nmol/L. Three rats given portal venous oleate infusions for 1 week had increased blood pressure compared with baseline (mean increase, 16 plus/minus 4 mm Hg). These studies indicate that increases in portal venous fatty acid concentrations have significant pressor effects, perhaps mediated by increased sympathetic tone. Chronic increases in portal venous fatty acid levels may be responsible for the hypertension that accompanies visceral obesity. (Hypertension. 1995;26:193-198.)