Role of lipolysis in postoral and oral fat preferences in mice.
Fatty acid receptors in the mouth and gut are implicated in the appetite for fat-rich foods. The role of lipolysis in oral- and postoral-based fat preferences of C57BL/6J mice was investigated by inhibiting lipase enzymes with orlistat. Experiment 1 showed that postoral lipolysis is required: mice learned to prefer (by 70%) a flavored solution paired with intragastric infusions of 5% soybean oil but not a flavor paired with soybean oil + orlistat (4 mg/g fat) infusions. Experiments 2-4 tested the oral attraction to oil in mice given brief choice tests that minimize postoral effects. In experiment 2, the same low orlistat dose did not reduce the strong (83-94%) preference for 2.5 or 5% soybean oil relative to fat-free vehicle in 3-min tests. Mice in experiment 3 given choice tests between two fat emulsions (2% triolein, corn oil, or soybean oil) with or without orlistat at a high dose (250 mg/g fat) preferred triolein (72%) and soybean oil (67%) without orlistat to the oil with orlistat but were indifferent to corn oil with and without orlistat. In experiment 4, mice preferred 2% triolein (62%) or soybean oil (89%) to vehicle when both choices contained orlistat (250 mg/g fat). Fatty acid receptors are thus essential for postoral but not oral-based preferences. Both triglyceride and fatty acid taste receptors may mediate oral fat preferences.
['Sclafani|Anthony|A|', 'Ackroff|Karen|K|']
D000284:Administration, Oral D000818:Animals D002755:Choice Behavior D003314:Corn Oil D004435:Eating D004791:Enzyme Inhibitors D005518:Food Preferences D008049:Lipase D008066:Lipolysis D008297:Male D008810:Mice, Inbred C57BL D000077403:Orlistat D013024:Soybean Oil D013649:Taste D014280:Triglycerides D014304:Triolein
orlistat intragastric infusions soybean oil corn oil triolein oil