Conversion of acetate to CO2, lipids, proteins, and lipoproteins during hemodialysis in humans.

Acetate-1-14C or acetate-2-14C was infused into the venous dialysis line in 17 chronic stable patients over a 4-hr period of standard hemodialysis. Radioactive CO2 in expired air was measured continuously during dialysis and for 20 hr postdialysis. Significantly more acetate-1-14C (56 +/- 2%) was recovered as 14CO2 in the expired air than was acetate-2-14C (49 +/- 3%). A total of 81% and 71% of the radioactivity was recovered from the expired air and expended dialysate from acetate-1-14C and acetate-2-14C, respectively. Of the remainder, a significant portion was incorporated into plasma lipids and proteins. Incorporation of radioactivity into phospholipids, cholesterol esters, and triglycerides increased during dialysis and continued to increase during the postdialysis period. Free fatty acid radioactivity increased during dialysis but declined afterwards. In the lipoprotein fractions radioactivities remained elevated at 24 hr in the LDL and HDL fractions, but declined in the VLDLs after this time interval.