Changes in plasma triglyceride metabolism during withdrawal of bile.

The relationship between bile acid turnover and plasma triglyceride metabolism was examined in a group of seven moderately overweight and hypertriglyceridemic men. Bile acid synthesis was stimulated by the continuous aspiration of duodenal contents so that 150% of the bile acid pool was removed in 18 hr. In comparison with the average concentration of very low density lipoprotein triglyceride (VLDL-TG) during a preceding 8-10 hr control period, bile withdrawal led to an increase in VLDL-TG of 34%, 43%, 32%, 14%, 26%, 14%, and 8% (mean +24%) in the seven men. In control studies performed on another day the mean change over a similar period of time, but without bile withdrawal, was +1% (p less than 0.01). The kinetics of VLDL triglyceride were studied in some of the subjects by analyzing the triglyceride specific radioactivity curves following injections of radiolabelled glycerol. In control studies of 26 hr duration the curves were resolved into two apparent exponential functions, the second part of the curve appearing between 15 and 18 hr after pulse-labeling. During bile withdrawal, the second apparent exponential developed sooner, within 4 hr of beginning the aspiration and coincided with the rise in triglyceride concentration. The fractional rate of the second exponential was at least as fast during bile withdrawal as during the control period despite the increase in VLDL-TG pool size, suggesting that the turnover of triglyceride was higher at a time when bile acid production was being stimulated.