Very-low-density lipoproteins in the fetal rat at term.

VLDL triglyceride influx into fetal serum and the composition of fetal serum VLDL was studied in rats at term. By use of the Triton WR 1339 method the rate of VLDL triglyceride influx into fetal circulation was calculated to be 0.1 mmol/h X 1 serum in comparison to 4.2 mmol/h X 1 in adult rats. Fetal VLDL exhibit a composition differing from that of adults. The experimental data indicate that the main fraction of fetal serum VLDL represents intermediates of VLDL metabolism converted already to apolipoprotein C-free, relatively triglyceride-depleted particles.