Abstract
Several studies have reported that parenteral lipid emulsions containing medium-chain triglycerides (MCT) and structured lipids (SL) are better utilized than those containing long-chain triglycerides (LCT). The objective of this study was to test the hypothesis that parenteral LCT require more extensive modification via hydrolysis and reesterification (triglyceride-free fatty acid [TG-FFA] recycling) for effective utilization, whereas MCT and SL do not. As an index of TG-FFA cycling activity, we measured glycerol and palmitate kinetics in rats (204 to 243 g) fed parenterally one of three isocaloric (250 kcal/kg/d) isonitrogenous (1.5 g N/kg/d) diets with half of the nonprotein energy from glucose and the rest from either LCT, LCT plus MCT, or SL for 5 days. Two experiments were performed. On day 5, rats were given a 7- to 8-hour infusion of either 5H2 Glycerol and 1-14C Palmitate bound to albumin to measure palmitate and glycerol kinetics (experiment 1), or U-13C glucose to determine the proportion of endogenous glycerol production derived from glucose (experiment 2). Data are presented as means ± SEM. Endogenous glycerol production was significantly higher with LCT (11.33 ± 2.89 mmol/kg/h) than with SL (2.91 ± 0.62 mmol/kg/h). The value for the physical mixture of LCT plus MCT (5.46 ± 1.29 mmol/kg/h) fell midway between that for LCT and SL (P = NS). There were no significant differences in palmitate kinetics or oxidation. The increased glycerol production is due to the mobilization of endogenous triglyceride and is consistent with a higher rate of TG-FFA cycling being involved in the metabolism of LCT than of SL. The energy expended in TG-FFA cycling with LCT can account for the apparent poorer caloric effectiveness of LCT when compared with SL.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 743-748 |
| Number of pages | 6 |
| Journal | Metabolism |
| Volume | 42 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jan 1 1993 |
| Externally published | Yes |
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All Science Journal Classification (ASJC) codes
- Endocrinology, Diabetes and Metabolism
- Endocrinology
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Glycerol kinetics with parenteral lipid emulsions (long-chain triglycerides, medium-chain triglycerides, and structured lipids) in rats. / Drews, D.; Schluter, M. D.; Stein, Thomas.
In: Metabolism, Vol. 42, No. 6, 01.01.1993, p. 743-748.Research output: Contribution to journal › Article
TY - JOUR
T1 - Glycerol kinetics with parenteral lipid emulsions (long-chain triglycerides, medium-chain triglycerides, and structured lipids) in rats
AU - Drews, D.
AU - Schluter, M. D.
AU - Stein, Thomas
PY - 1993/1/1
Y1 - 1993/1/1
N2 - Several studies have reported that parenteral lipid emulsions containing medium-chain triglycerides (MCT) and structured lipids (SL) are better utilized than those containing long-chain triglycerides (LCT). The objective of this study was to test the hypothesis that parenteral LCT require more extensive modification via hydrolysis and reesterification (triglyceride-free fatty acid [TG-FFA] recycling) for effective utilization, whereas MCT and SL do not. As an index of TG-FFA cycling activity, we measured glycerol and palmitate kinetics in rats (204 to 243 g) fed parenterally one of three isocaloric (250 kcal/kg/d) isonitrogenous (1.5 g N/kg/d) diets with half of the nonprotein energy from glucose and the rest from either LCT, LCT plus MCT, or SL for 5 days. Two experiments were performed. On day 5, rats were given a 7- to 8-hour infusion of either 5H2 Glycerol and 1-14C Palmitate bound to albumin to measure palmitate and glycerol kinetics (experiment 1), or U-13C glucose to determine the proportion of endogenous glycerol production derived from glucose (experiment 2). Data are presented as means ± SEM. Endogenous glycerol production was significantly higher with LCT (11.33 ± 2.89 mmol/kg/h) than with SL (2.91 ± 0.62 mmol/kg/h). The value for the physical mixture of LCT plus MCT (5.46 ± 1.29 mmol/kg/h) fell midway between that for LCT and SL (P = NS). There were no significant differences in palmitate kinetics or oxidation. The increased glycerol production is due to the mobilization of endogenous triglyceride and is consistent with a higher rate of TG-FFA cycling being involved in the metabolism of LCT than of SL. The energy expended in TG-FFA cycling with LCT can account for the apparent poorer caloric effectiveness of LCT when compared with SL.
AB - Several studies have reported that parenteral lipid emulsions containing medium-chain triglycerides (MCT) and structured lipids (SL) are better utilized than those containing long-chain triglycerides (LCT). The objective of this study was to test the hypothesis that parenteral LCT require more extensive modification via hydrolysis and reesterification (triglyceride-free fatty acid [TG-FFA] recycling) for effective utilization, whereas MCT and SL do not. As an index of TG-FFA cycling activity, we measured glycerol and palmitate kinetics in rats (204 to 243 g) fed parenterally one of three isocaloric (250 kcal/kg/d) isonitrogenous (1.5 g N/kg/d) diets with half of the nonprotein energy from glucose and the rest from either LCT, LCT plus MCT, or SL for 5 days. Two experiments were performed. On day 5, rats were given a 7- to 8-hour infusion of either 5H2 Glycerol and 1-14C Palmitate bound to albumin to measure palmitate and glycerol kinetics (experiment 1), or U-13C glucose to determine the proportion of endogenous glycerol production derived from glucose (experiment 2). Data are presented as means ± SEM. Endogenous glycerol production was significantly higher with LCT (11.33 ± 2.89 mmol/kg/h) than with SL (2.91 ± 0.62 mmol/kg/h). The value for the physical mixture of LCT plus MCT (5.46 ± 1.29 mmol/kg/h) fell midway between that for LCT and SL (P = NS). There were no significant differences in palmitate kinetics or oxidation. The increased glycerol production is due to the mobilization of endogenous triglyceride and is consistent with a higher rate of TG-FFA cycling being involved in the metabolism of LCT than of SL. The energy expended in TG-FFA cycling with LCT can account for the apparent poorer caloric effectiveness of LCT when compared with SL.
UR - http://www.scopus.com/inward/record.url?scp=0027211725&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0027211725&partnerID=8YFLogxK
U2 - 10.1016/0026-0495(93)90243-H
DO - 10.1016/0026-0495(93)90243-H
M3 - Article
C2 - 8510520
AN - SCOPUS:0027211725
VL - 42
SP - 743
EP - 748
JO - Metabolism: Clinical and Experimental
JF - Metabolism: Clinical and Experimental
SN - 0026-0495
IS - 6
ER -