Postprandial plasma triacylglycerols in rats under alpha 1-adrenergic blockade.
The present studies evaluated the effect of prazosin, a selective alpha 1-adrenergic antagonist, on some metabolic determinants of triacylglycerol-rich lipoproteins. Plasma triacylglycerols (TG), TG secretion rate, TG removal rate, plasma insulin, and glucose were evaluated postprandially in animals fed a high-sucrose meal. In the fasted state plasma TG, glucose, and insulin concentrations were minimally affected by prazosin. There was a significant postprandial elevation in plasma TG levels that was larger after ingestion of a meal containing corn oil than after intake of a fat-free meal. Prazosin totally blunted the postprandial elevation in plasma TG independently of the presence (P < 0.004) or absence of dietary fat (P < 0.01). In the postprandial phase after ingestion of a fat-free, high-sucrose meal, prazosin decreased the rate of secretion of TG into the circulation (-54%, P < 0.0003) and accelerated twofold the clearance of an injected fat emulsion (P < 0.02). The postprandial elevations in plasma insulin and glucose were significantly potentiated by administration of prazosin before intake of the fat-free meal. These results indicate that prazosin prevented the postprandial elevation in plasma TG that followed the ingestion of a high-sucrose meal. The results also demonstrate that the alpha 1-blocker exerted its action both by decreasing TG secretion and by increasing the rate of removal of circulating TG.
Deshaies
Y
Y
Department of Physiology, School of Medicine, Laval University, Quebec, Canada.
Belahsen
R
R
D000704:Analysis of Variance; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D003902:Detergents / Q000494:pharmacology; D004040:Dietary Carbohydrates / Q000378:metabolism* / Q000494:pharmacology; D004435:Eating / Q000502:physiology*; D007328:Insulin / Q000097:blood; D011092:Polyethylene Glycols / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D013997:Time Factors; D014280:Triglycerides / Q000097:blood*
D001786:Blood Glucose; D003902:Detergents; D004040:Dietary Carbohydrates; D007328:Insulin; D014280:Triglycerides; D011092:Polyethylene Glycols; D011224:Prazosin; C016811:tyloxapol