title: Desaturation index versus isotopically measured de novo lipogenesis as an indicator of acute systemic lipogenesis.
abstract: BACKGROUND
  High carbohydrate feeding is known to increase plasma triglycerides as well as hepatic de novo lipogenesis (DNL) and may be implicated in the development of hepatic insulin resistance and fatty liver. Unfortunately, it is technically challenging to determine what proportion of circulating plasma triglycerides have been derived from the newly synthesized fatty acids in the postprandial period. The aims of this study were to 1) characterize the changes in the plasma postprandial total fatty acid pool in beagles following the consumption of meals containing 44% (Control) and 74% (High Sucrose) carbohydrate and 2) determine if changes in plasma fatty acid concentration and delta-9 desaturation index (DI) would be useful as simple and easy to measure biomarkers of systemic DNL.
  
  
  RESULTS
  No differences in plasma total palmitic acid (16:0), stearic acid (18:0) and oleic acid (18:1) concentrations or delta-9 DI for the total 18:0 and 18:1 pools between High Sucrose and Controls were observed. However, newly synthesized 16:0 (2.6 ± 0.2% vs. 8.8 ± 2.0%; p = 0.016), 18:0 (0.93 ± 0.2% vs. 4.1 ± 1.7%; p = 0.007) and 18:1 (0.29 ± 0.09% vs. 3.5 ± 1.2%; p = 0.017) were higher in High Sucrose versus Control animals, respectively. Also, the delta-9 DI for the newly synthesized 18:0 and 18:1 pools was higher at 2 and 6 hours postprandial, with a pattern of change which supports the increased stearoyl-CoA desaturase (SCD-1) activity following high carbohydrate feeding followed by a down regulation of this enzyme.
  
  
  CONCLUSIONS
  Our data show that high sucrose meals increase the relative contribution of systemic DNL produced fatty acids to the total postprandial plasma fatty acid pool. These data also show that a different pattern of both fatty acid synthesis and disposal occurs depending on energy and macronutrient profile of the meal. These changes are in spite of no observable changes in the plasma concentrations or ratios of the total fatty acid pool opposed to the observed changes in the newly synthesized fatty acid pool.
authors: Diabetes and Nutritional Sciences Division, King's College London, 150 Stamford Street, London, SE1 9NH, UK. scott.harding@kcl.ac.uk.
authors: Scott V
authors: SV
authors: Harding
authors: Department of Pharmacokinetics, Pharmacodynamics and Drug Metabolism, Merck, One Merck Drive, Whitehouse Station, NJ, 08889, USA. kevin_bateman@merck.com.
authors: Kevin P
authors: KP
authors: Bateman
authors: Kaneq Pharma, Montreal, QC, Canada. brian.kennedy@kaneq.ca.|Previously at Department of Biochemistry and Molecular Biology at the Merck Frosst Center for Therapeutic Research, Montreal, QC, Canada. brian.kennedy@kaneq.ca.
authors: Brian P
authors: BP
authors: Kennedy
authors: Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, 14214, USA. rideout@buffalo.edu.
authors: Todd C
authors: TC
authors: Rideout
authors: Richardson Centre for Functional Foods and Nutraceuticals, University of Manitoba, Winnipeg, R3T 6C5, MB, Canada. peter.jones@umanitoba.ca.
authors: Peter J H
authors: PJ
authors: Jones
mesh_terms: D000818:Animals; D004040:Dietary Carbohydrates / Q000008:administration & dosage* / Q000378:metabolism; D004285:Dogs; D050155:Lipogenesis / Q000187:drug effects* / Q000502:physiology; D008297:Male; D019301:Oleic Acid / Q000096:biosynthesis / Q000097:blood; D019308:Palmitic Acid / Q000097:blood; D019518:Postprandial Period; D013229:Stearic Acids / Q000097:blood; D013230:Stearoyl-CoA Desaturase / Q000097:blood*; D013395:Sucrose / Q000008:administration & dosage* / Q000378:metabolism; D014280:Triglycerides / Q000097:blood
chemical_list: D004040:Dietary Carbohydrates; D013229:Stearic Acids; D014280:Triglycerides; D019301:Oleic Acid; D019308:Palmitic Acid; C031183:stearic acid; D013395:Sucrose; D013230:Stearoyl-CoA Desaturase