We intend to continue studies on the correlation of the ratio of free to esterified cholesterol in the chromatin-bound cholesterol in rat liver with changes in the activity of 3-hydroxy-3-methyl glutaryl CoA reductase and with synthesis of cholesterol from acetate. Changes in cholesterol synthesis occurring during the circadian cycle and those produced by starvation, cholesterol feeding and other procedures will be studied in this respect. We are also continuing the purification of the cholesterol receptor protein in liver cytosol and will investigate its role in the transport of cholesterol inside the liver cell, particularly from the plasma membrane to the nucleus.