Effect of medium‐ and long‐chain triglyceride infusion on lipoprotein and hepatic lipase in healthy subjects

Abstract

Plasma lipolytic activity and hydrolysis of intravenous fat were studied in six healthy subjects during infusion of a long-chain triglyceride (LCT) fat emulsion (Intralipid 20%) or of a medium-chain triglyceride (MCT)/LCT emulsion (Lipofundin MCT 20%). The fat emulsions were infused continuously at a rate of 0.17 g triglyceride kg-1 body weight (BW)h-1 for 6 h in random order at 7-day intervals. A continuous infusion of glucose (0.18 g kg-1 BW h-1) was administered for a period of 7 h and was started 1 h before the lipid infusion. Infusions of both types of fat increased plasma triglyceride (TG), free fatty acid (FFA) and lipoprotein lipase (LPL) levels and steady-state values were present during the 3rd to 5th h of infusion. MCT/LCT infusion resulted in higher plasma levels at steady-state of TG (3.63 +/- 0.45 [SEM] vs 2.73 +/- 0.45 mmol l-1; P less than 0.05), FFA (1.05 +/- 0.08 vs 0.54 +/- 0.04 mmol l-1; P less than 0.01) and LPL (4.6 +/- 0.6 vs 2.6 +/- 0.5 mU ml-1; P less than 0.05) in comparison with LCT administration. There was a positive correlation between plasma LPL activity and TG concentration (r = 0.77; P less than 0.001) when data for the two infusions were combined. Although the same amount of fat was infused on a weight basis, the molar infusion rate was 40% higher with MCT/LCT than with LCT infusion, due to differences in molecular weights (634 vs 885 Da).(ABSTRACT TRUNCATED AT 250 WORDS)

On the role of glucose-dependent insulintropic polypeptide in postprandial metabolism in humans

“…As shown in Fig. 6 and in agreement with a previous study (35), the kinetics of removal of TAG from the circulation was strictly first order with the same rate constants on the 4 experimental days with the infusion of Intralipid. Our inability to demonstrate any effect of GIP therefore is hardly due to saturation of the LPL activity due to the high plasma TAG concentration applied, because saturation would result in deviation from first order kinetics.…”

Effects of intravenous supplementation with α-tocopherol in patients receiving total parenteral nutrition containing medium- and long-chain triglycerides

“…Moreover, the molar clearance rates of MCT=LCT and LCT infusions by hepatic and lipoprotein lipases have been shown to be similar (Nordenström et al, 1991;Treskova et al, 1999). Thus our data cannot demonstrate any significant changes in serum triglycerides and suggest that the protection of the lipoprotein particles against peroxidation, at least that induced by copper in vitro, is determined by the increase in a-tocopherol relative rather than by any changes in serum cholesterol or triglycerides.…”

Parenteral and enteral metabolism of anaplerotic triheptanoin in normal rats. II. Effects on lipolysis, glucose production, and liver acyl-CoA profile

“…It is well known that the infusion of a triglyceride emulsion (even-long chain or mixed even-long ϩ even-medium chain) induces the activation of plasma lipoprotein lipase, which hydrolyzes the infused triglyceride (13). In addition, human studies based on arterio-venous differences in fatty acid concentration across adipose tissue and the arm provided evidence that the infusion of a triglyceride emulsion (intralipid) results in an increase in long-chain fatty acid release from adipose tissue (5,6,21).…”