title: Intravenous niacin acutely improves the efficiency of dietary fat storage in lean and obese humans.
abstract: Spillover of fatty acids released by lipoprotein lipase hydrolysis of meal triglycerides may be a major contributor to the free fatty acid (FFA) pool. We studied lean (n = 6) and overweight and obese (n = 5) subjects during continuous feeding on two occasions: during intravenous infusion of niacin (2.8 mg/min) and saline. After establishment of steady-state chylomicronemia and suppression of adipose tissue lipolysis with a liquid meal, spillover was measured with infusions of [U-(13)C]oleate and [(3)H]triolein. Total FFA concentrations were lower during niacin infusion in both lean (50 ± 4 vs. 102 ± 7 μmol/L; P < 0.002) and obese (75 ± 6 vs. 143 ± 13 μmol/L; P < 0.01) subjects. Oleate appearance was lower during niacin infusion than during saline infusion in both lean (21 ± 2 vs. 32 ± 5 μmol/min; P = 0.07) and obese subjects (25 ± 3 vs. 46 ± 8 μmol/min; P < 0.02). Spillover was lower during niacin infusion than during saline infusion in lean (21 ± 4 vs. 29 ± 3%) and obese (21 ± 2 vs. 29 ± 5%) subjects (P < 0.03 for both). In summary, during meal absorption, niacin produces additional suppression of lipolysis and a reduction in fractional spillover compared with saline in both normal and obese subjects. Infusion of intravenous niacin provides a model for acutely improving dietary fat storage, perhaps by suppressing lipolysis in visceral adipose tissue.
authors.affiliation: Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Nelson
authors.forename: Danielle
authors.initials: D
authors.lastname: Vlazny
authors.forename: Almira
authors.initials: A
authors.lastname: Smailovic
authors.forename: John M
authors.initials: JM
authors.lastname: Miles
mesh_terms: D061605:Administration, Intravenous; D000328:Adult; D004041:Dietary Fats / Q000378:metabolism; D050171:Dyslipidemias / Q000378:metabolism; D005260:Female; D006801:Humans; D050152:Intra-Abdominal Fat / Q000187:drug effects / Q000378:metabolism; D050356:Lipid Metabolism / Q000187:drug effects; D008066:Lipolysis / Q000187:drug effects; D008297:Male; D009525:Niacin / Q000008:administration & dosage* / Q000494:pharmacology*; D009765:Obesity / Q000378:metabolism*; D050177:Overweight / Q000378:metabolism*; D013851:Thinness / Q000378:metabolism*
chemical_list: D004041:Dietary Fats; D009525:Niacin