title: Effects of isomers of conjugated linoleic acid on porcine adipocyte growth and differentiation.
abstract: Conjugated linoleic acids (CLAs) decrease fat deposition in mammals, including pigs. To determine mechanisms for CLA effects on adipocyte growth, porcine stromal-vascular cells (preadipocytes) were isolated and plated in medium containing 10% fetal bovine serum. After 24 h, differentiation factors (insulin + hydrocortisone + transferrin) were added. Oleic acid (200 microM) was added to some plates as a positive control. One of two isomers of CLA (50 microM cis 9, trans 11 or >50 microM trans 10, cis 12), or a mixture of the two isomers (25 microM each) was added to other plates. The cell number increased 7+ times in 7 days after initiation of differentiation, and was not different among treatment groups. By 7 days, Oil Red O-stained material (OROSM), expressed per cell, increased 10+ times in control cells and 64 times in oleic acid-treated cells. Addition of either isomer of CLA or the mixture caused OROSM/cell to increase 10+ times at 2 days, with no further increase at later times. In CLA-treated cells there was no increase in peroxisome proliferator-activated receptor gamma (PPARgamma) or lipoprotein lipase mRNA concentrations. The increased OROSM/cell may represent triacylglycerol synthesis from medium CLA using existing biosynthetic capacity or provision of a limiting ligand for PPARgamma already present. The results are different from those observed with rodent-derived clonal cells (3T3-L1 cells), wherein proliferation and differentiation are inhibited by CLAs, and the active isomer is trans 10, cis 12-CLA. The results suggest distinctions between clonal and primary preadipocytes, or species differences.
authors.affiliation: USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030-2600, USA.
authors.forename: Ronald L
authors.initials: RL
authors.lastname: McNeel
authors.forename: Harry J
authors.initials: HJ
authors.lastname: Mersmann
mesh_terms: D017667:Adipocytes / Q000166:cytology* / Q000187:drug effects*; D000818:Animals; D001391:Azo Compounds; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects*; D002478:Cells, Cultured; D004396:Coloring Agents; D006854:Hydrocortisone / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D007536:Isomerism; D019787:Linoleic Acid / Q000494:pharmacology*; D008071:Lipoprotein Lipase / Q000235:genetics; D019301:Oleic Acid / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics; D013552:Swine; D014157:Transcription Factors / Q000235:genetics; D014168:Transferrin / Q000494:pharmacology
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D007328:Insulin; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; D014168:Transferrin; D019301:Oleic Acid; D019787:Linoleic Acid; D008071:Lipoprotein Lipase; C011049:oil red O; D006854:Hydrocortisone