Effect of preduodenal lipase inhibition in suckling rats on dietary octanoic acid (C8:0) gastric absorption and plasma octanoylated ghrelin concentration.
Part of medium chain fatty acids (MCFAs) coming from dietary triglycerides (TGs) can be directly absorbed through the gastric mucosa after the action of preduodenal lipase (lingual lipase in the rat). MCFA gastric absorption, particularly that of octanoic acid (C8:0), may have a physiological importance in the octanoylation of ghrelin, the orexigenic gastric peptide acting as an endogenous ligand of the hypothalamic growth hormone secretagogue receptor 1a (GHSR-1a). However, the amount of C8:0 absorbed in the stomach and its metabolic fate still haven't been clearly characterized. The purpose of the present study was to further characterize and quantify the importance of preduodenal lipase activity on the release and gastric absorption of dietary C8:0 and on the subsequent ghrelin octanoylation in the stomach mucosa. Fifteen days old rats received fat emulsions containing triolein or [1,1,1-(13)C]-Tri-C8:0 and a specific inhibitor of preduodenal lipase, 5-(2-(benzyloxy)ethoxy)-3-(3-phenoxyphenyl)-1,3,4-oxadiazol-2(3H)-one or BemPPOX. The fate of the (13)C-C8:0 was followed in rat tissues after 30 and 120min of digestion and octanoylated ghrelin was measured in the plasma. This work (1) demonstrates that part of C8:0 coming from Tri-C8:0 is directly absorbed at the gastric level, (2) allows the estimation of C8:0 gastric absorption level (1.3% of the (13)C-C8:0 in sn-3 position after 30min of digestion), as well as (3) the contribution of rat lingual lipase to total lipolysis and to duodenal absorption of dietary FAs (at least 30%), (4) shows no short-term effect of dietary Tri-C8:0 consumption and subsequent increase of C8:0 gastric tissue content on plasma octanoylated ghrelin concentration.
Agrocampus Ouest-INRA, USC 1378, Laboratoire de Biochimie et Nutrition Humaine, Rennes, France.
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Lemarié
CNRS, Aix-Marseille Université, UMR 7282, Enzymologie Interfaciale et de Physiologie de la Lipolyse, Marseille, France.
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Cavalier
Agrocampus Ouest-INRA, USC 1378, Laboratoire de Biochimie et Nutrition Humaine, Rennes, France.
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Garcia
Agrocampus Ouest-INRA, USC 1378, Laboratoire de Biochimie et Nutrition Humaine, Rennes, France.
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Boissel
CNRS, Aix-Marseille Université, UMR 7282, Enzymologie Interfaciale et de Physiologie de la Lipolyse, Marseille, France.
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Point
Agrocampus Ouest-INRA, USC 1378, Laboratoire de Biochimie et Nutrition Humaine, Rennes, France.
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Catheline
Agrocampus Ouest-INRA, USC 1378, Laboratoire de Biochimie et Nutrition Humaine, Rennes, France.
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Legrand
CNRS, Aix-Marseille Université, UMR 7282, Enzymologie Interfaciale et de Physiologie de la Lipolyse, Marseille, France.
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Carrière
Agrocampus Ouest-INRA, USC 1378, Laboratoire de Biochimie et Nutrition Humaine, Rennes, France. Electronic address: vincent.rioux@agrocampus-ouest.fr.
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Rioux
D000818:Animals; D002210:Caprylates / Q000008:administration & dosage / Q000097:blood*; D005227:Fatty Acids / Q000378:metabolism*; D065570:Gastric Absorption / Q000187:drug effects / Q000235:genetics; D005753:Gastric Mucosa / Q000378:metabolism; D054439:Ghrelin / Q000097:blood*; D008049:Lipase / Q000037:antagonists & inhibitors* / Q000097:blood; D008066:Lipolysis / Q000187:drug effects; D051381:Rats; D014280:Triglycerides / Q000008:administration & dosage
D002210:Caprylates; D005227:Fatty Acids; D054439:Ghrelin; D014280:Triglycerides; D008049:Lipase; C031492:octanoic acid
Acylation; Gastric absorption; Gastric mucosa; Ghrelin; Ghrelin O-acyltransferase; Lingual lipase; Octanoic acid; Octanoylation; Preduodenal lipase