The effect of dietary fat or cholesterol and cholic acid on the rate of synthesis of rat liver glucose-6-P dehydrogenase.

The effect of dietary fat or cholesterol and cholic acid on the rate of synthesis of rat liver glucose-6-P dehydrogenase was measured by isolating hepatocytes from the livers of rats fed diets containing various amounts and types of lipid. Hepatocyte proteins were labeled with [3H]leucine and glucose-6-P dehydrogenase was immunoprecipitated with a specific antiserum. The immunoprecipitates were electrophoresed on sodium dodecyl sulfate-polyacrylamide gels and the radioactivity in the glucose-6-P dehydrogenase subunit was used to calculate the relative rate of synthesis of the enzyme. It is concluded that the activity of glucose-6-P dehydrogenase is primarily regulated by alterations in the rate at which the enzyme is synthesized. Dietary fat may decrease the rate of degradation of glucose-6-P dehydrogenase.