Plasma kinetics of a chylomicron-like emulsion in normolipidemic obese women after a short-period weight loss by energy-restricted diet.
Chylomicrons carry dietary fats in the bloodstream for storage in body tissues, and thus play an important role in obesity. The 2-step chylomicron metabolism consists of lipolysis by lipoprotein lipase (LPL) on vessel walls and hepatic uptake of triglyceride-depleted remnants. A triglyceride-rich emulsion that mimics chylomicrons, labeled with [9,10-(3)H]glycerol-trioleate (TG) and [1-(14)C] cholesteryl-oleate (CE) was intravenously injected into 14 obese women with body mass index between 30 and 40 kg/m(2) (age, 30 to 40 years), before and after a 2-month energy-restricted diet and into non-obese controls for determination of radioactive lipid plasma kinetics. TG kinetics evaluates lipolysis, whereas CE kinetics evaluates remnant removal. The emulsion TG fractional clearance rate (FCR, in min(-1)) was similar in obese women and their controls (0.126 +/- 0.065; controls, 0.111 +/- 0.031), but the CE-FCR was pronouncedly reduced in the obese subjects (0.028 +/- 0.014; controls, 0.070 +/- 0.009 min(-1); P <.0001). After the energy-restricted diet, TG-FCR was reduced in the obese women (0.075 +/- 0.044 min(-1); P <.05), but CE-FCR was unchanged (0.032 +/- 0.025 min(-1)). Therefore, the lipolysis of the chylomicron-like emulsion is normal in obese women, but remnant removal from the plasma is diminished. After active weight loss by an energy-restricted diet, the remnant removal was unchanged but lipolysis was diminished, possibly due to adaptative changes in LPL activity.
Oliveira
M R M
MR
Faculty of Pharmaceutical Sciences, and Heart Institute of the Medical School Hospital (INCOR-HCFMUSP), University of São Paulo, Brazil.
Maranhão
R C
RC
D000328:Adult; D000886:Anthropometry; D001053:Apolipoproteins / Q000097:blood; D001786:Blood Glucose / Q000032:analysis; D002914:Chylomicrons / Q000097:blood*; D004032:Diet; D018752:Diet, Fat-Restricted; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004655:Emulsions; D005260:Female; D006801:Humans; D007700:Kinetics; D008055:Lipids / Q000097:blood*; D009765:Obesity / Q000097:blood* / Q000178:diet therapy* / Q000473:pathology; D012016:Reference Values; D013997:Time Factors; D015431:Weight Loss
D001053:Apolipoproteins; D001786:Blood Glucose; D002914:Chylomicrons; D004040:Dietary Carbohydrates; D004655:Emulsions; D008055:Lipids