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.
Faculty of Pharmaceutical Sciences, and Heart Institute of the Medical School Hospital (INCOR-HCFMUSP), University of São Paulo, Brazil.
M R M
MR
Oliveira
R C
RC
Maranhão
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