Structure-activity relationship of conjugated linoleic acid and its cognates in inhibiting heparin-releasable lipoprotein lipase and glycerol release from fully differentiated 3T3-L1 adipocytes.
Conjugated linoleic acid (CLA) reduces body fat in part by inhibiting the activity of heparin-releasable lipoprotein lipase (HR-LPL) activity in adipocytes, an effect that is induced by the trans-10,cis-12 CLA isomer. In this study we used a series of compounds that are structurally related to CLA (i.e., CLA cognates) to investigate the structural basis for this phenomenon. None of the 18:1 CLA cognates that were tested, nor trans-9,cis-12 18:2, cis-12-octadecen-10-ynoic acid (10y,cis-12) or 11-(2'-(n-pentyl)phenyl)-10-undecylenic acid (designated P-t10), exhibited any significant effect on HR-LPL activity. Among the CLA derivatives (alcohol, amide, and chloride) that were tested, only the alcohol form inhibited HR-LPL activity, although to a lesser extent than CLA itself. In addition, intracellular TG was reduced only by trans-10,cis-12 CLA and the alcohol form of CLA. Hence it appears that the trans-10,cis-12 conjugated double bond in conjunction with a carboxyl group at C-1 is required for inhibition of HR-LPL activity, and that an alcohol group can partially substitute for the carboxyl group. We also studied glycerol release from the cells, observing that this was enhanced by trans-10 18:1, trans-13 18:1, cis-12 18:1, cis-13 18:1, P-t10 but was reduced by cis-9 18:1, the alcohol and amide forms of CLA or 10y,cis-12. Accordingly the structural feature or features involved in regulating lipolysis appear to be more complex. Despite enhancing lipolysis in cultured 3T3-L1 adipocytes, trans-10 18:1 did not reduce body fat gain when fed to mice.
Park
Yeonhwa
Y
Food Research Institute, University of Wisconsin-Madison, 1925 Willow Drive, Madison, WI 53706, USA.
Storkson
Jayne M
JM
Liu
Wei
W
Albright
Karen J
KJ
Cook
Mark E
ME
Pariza
Michael W
MW
D041721:3T3-L1 Cells / Q000187:drug effects; D017667:Adipocytes / Q000187:drug effects / Q000201:enzymology*; D000818:Animals; D001823:Body Composition; D002454:Cell Differentiation / Q000187:drug effects; D005990:Glycerol / Q000378:metabolism*; D006493:Heparin / Q000378:metabolism; D007536:Isomerism; D044243:Linoleic Acids, Conjugated / Q000737:chemistry* / Q000494:pharmacology*; D008071:Lipoprotein Lipase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D013329:Structure-Activity Relationship; D014280:Triglycerides / Q000378:metabolism
D044243:Linoleic Acids, Conjugated; D014280:Triglycerides; D006493:Heparin; D008071:Lipoprotein Lipase; D005990:Glycerol