The effect of a plasma protein fraction on lipid synthesis in cultured skin fibroblasts from normals and patients with hyperapobetalipoproteinemia.

Lipid synthesis was measured in cultured skin fibroblasts obtained from normals and patients with Hyperapobetalipoproteinemia (HyperapoB). Using lipoprotein-deficient serum medium, triglyceride synthesis and cholesterol esterification were greater in normals than in HyperapoB due to differences in de novo synthesis, not to differences in re-esterification or to different rates of hydrolysis. When normal and HyperapoB cells were incubated in serum-free medium, however, lipid synthesis was the same. Serum was then fractionated chromatographically and a partially purified protein fraction shown to be responsible for the stimulatory effect in normals.