title: Protocol for the measurement of fatty acid and glycerol turnover in vivo in baboons.
abstract: Recognition of the strength of nonhuman primate models in investigating metabolic disorders has resulted in an expanded need for in vivo research techniques. We studied adipose metabolism in 10 baboons (13.0 ± 4.2 years old, 29.5 ± 5.5 kg). Part 1 evaluated the effect of different sedatives on the rate of appearance of plasma free fatty acids (RaFFA), assessed using ¹³C₄-labeled palmitate infusion (7 µmol/kg/min). Animals, were studied with no sedation, with complete isoflurane sedation, and with minimal midazolam infusion (0.04 mg/kg/h), with the last scheme allowing for the most consistent values and animals that were visually more calm. In Part 2, RaFFA and RaGlycerol (D₅-glycerol, 5 mg/kg lean body mass/h) were measured. From midnight to 0300, flux fell and came to a steady state between 0500 and 0700 h (RaFFA, 39.4 ± 29.8 μmol/kg fat mass/min; and RaGlycerol, 26.9 ± 7.3 μmol/kg/min). The RaFFA-to-RaGlycerol ratio was 1.5 ± 0.8 (49% reesterification). The decline in turnover throughout the night reflects natural circadian processes and was mirrored by reductions in FFA and glycerol to 0.62 and ± 0.14 and 0.16 and ± 0.03 mmol/l, respectively. The concurrent changes in both FFA and glycerol kinetics indicate physiologic validity of the method. These techniques will support needed research to determine mechanisms by which treatments act upon the adipocyte in vivo.
authors.affiliation: Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX.
authors.forename: Raul A
authors.initials: RA
authors.lastname: Bastarrachea
authors.affiliation: Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: Sonya M
authors.initials: SM
authors.lastname: Veron
authors.affiliation: Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: Vidya
authors.initials: V
authors.lastname: Vaidyanathan
authors.affiliation: Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX.
authors.forename: Maggie
authors.initials: M
authors.lastname: Garcia-Forey
authors.affiliation: Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX.
authors.forename: V Saroja
authors.initials: VS
authors.lastname: Voruganti
authors.affiliation: Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX.
authors.forename: Paul B
authors.initials: PB
authors.lastname: Higgins
authors.affiliation: Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX. Electronic address: Elizabeth.parks@utsouthwestern.edu.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Parks
mesh_terms: D017667:Adipocytes / Q000378:metabolism; D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001786:Blood Glucose / Q000032:analysis; D001823:Body Composition; D002247:Carbon Isotopes / Q000032:analysis; D005215:Fasting / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005260:Female; D005990:Glycerol / Q000097:blood / Q000493:pharmacokinetics; D006993:Hypnotics and Sedatives / Q000008:administration & dosage; D007328:Insulin / Q000097:blood; D007553:Isotope Labeling; D007700:Kinetics; D008297:Male; D009765:Obesity / Q000378:metabolism; D010168:Palmitates / Q000378:metabolism*; D010215:Papio / Q000378:metabolism*
chemical_list: D001786:Blood Glucose; D002247:Carbon Isotopes; D005230:Fatty Acids, Nonesterified; D006993:Hypnotics and Sedatives; D007328:Insulin; D010168:Palmitates; D005990:Glycerol