Stimulation of the synthesis of very low density lipoproteins in rooster liver by estradiol

A sensitive, specific, and rapid immunochemical method for the measurement of the synthesis of lipoproteins in rooster liver is described. Incubation of liver slices with [³H]leucine resulted in the incorporation of radioactivity into protein material that could be precipitated from crude extracts by a monospecific antibody directed against the antigen common to plasma very low density and low density lipoproteins (very low density lipoprotein antigen). Use of this assay permitted the demonstration of a 4 fold increase in the rate of hepatic synthesis of the very low density lipoprotein antigen occurring 16 hr after the administration of estrogen to roosters. Since under these conditions as much as 18% of the total protein synthesized by the rooster liver represented very low density lipoprotein antigen, this system may provide a model for studying not only the effect of a steroid hormone on specific gene expression but also the mechanism of regulation of very low density lipoprotein synthesis in higher animals.