Physiological mechanism by which acetyl CoA carboxylase is regulated

Summary Compared with rats fed a normal diet, the activity of the protein inhibitor of acetyl CoA carboxylase in rat liver doubled after 48 h of fasting. Conversely, acetyl CoA carboxylase activity was diminished by nearly one half. In animals fasted and then subsequently refed a fat free diet, acetyl CoA carboxylase activity was elevated by nearly 9-fold, with a concomitant decrease in the activity of the protein inhibitor by about 9-fold as compared to fasted rats. Hence it appears that the regulatory protein inhibitor for acetyl CoA carboxylase is of physiological significance for fatty acid biosynthesis.This work supported by grants AM 01383 and AM 21148 from the National Institute of Artheritis, Metabolic and Digestive Disease. We thank Dr J. Porter for his support.