Effects of isomers of conjugated linoleic acid on porcine adipocyte growth and differentiation.
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.
McNeel
Ronald L
RL
USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030-2600, USA.
Mersmann
Harry J
HJ
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
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