ELIMINATION RATE OF FAT EMULSION PARTICLES FROM PLASMA IN JAPANESE SUBJECTS AS DETERMINED BY A TRIGLYCERIDE CLAMP TECHNIQUE

The elimination rate of emulsion triglyceride (TG) from plasma was inv estigated in Japanese subjects by a plasma TG clamp technique. Two dif ferent studies were performed. In Study 1, a lipid emulsion (20% long- chain triglyceride emulsion: LCT) was infused into a healthy research associate to achieve a certain concentration of TG in the plasma. Ther eafter, the infusion rate was adjusted to maintain the chosen concentr ations of TG in plasma (namely, 4-5 mmol/L, 3-4 mmol/L, and approximat ely 2 mmol/L) over a period of 160 min by measuring plasma TG concentr ations at 10-min intervals. Concentrations of TG in plasma were clampe d within 2.13 +/- 0.13 mmol/L by an infusion rate of 0.10 g . kg(-1). h(-1), within 3.34 +/- 0.20 mmol/L by an infusion rate of 0.14 g . kg( -1). h(-1), and within 4.46 +/- 0.22 mmol/L by an infusion rate of 0.1 1 g . kg(-1). h(-1). The mean rate of infusion of emulsified TG that h ad maintained the steady concentrations of TG in plasma was limited to the very narrow range of 0.12 +/- 0.02 g of TG . kg(-1). h(-1) regard less of the chosen concentration of TG in plasma. Concentrations of no nesterified fatty acids (NEFA) also remained at a fixed level of 1.378 +/- 0.103 mEq/L regardless of the chosen concentration of TG in the p lasma. Study 2 was undertaken to determine whether plasma TG concentra tion reached a plateau during a period when emulsion TG was infused in to three different subjects at a rate of 0.12 g . kg(-1). h(-1). The p lasma TG concentrations were steady at a level of 2.04 +/- 0.32 mmol/L , and the plasma NEFA concentrations remained at a fixed level of 1.33 +/- 0.13 mEq/L, over a period of 160 min after 50-min priming infusio n. These results indicate that the plasma TG elimination rate was limi ted to the narrow range of 0.12 +/- 0.02 g . kg(-1). h(-1) when the fa t emulsion was infused into Japanese subjects in a steady state. Howev er, the plasma TG elimination rate in Japanese subjects appeared to be lower than that of Europeans. This may be due to a difference in lipo protein Lipase activity caused by different dietary habits, namely, a lower fat intake.