Changes in the ratio of branched-chain to aromatic amino acids affect the secretion of albumin in cultured rat hepatocytes.

The effect of branched-chain amino acids (BCAAs) on the synthesis and secretion of albumin was studied in the primary cultures of rat hepatocytes. The changes in the normal BCAAs/aromatic amino acids (AAAs) ratio reduced the secretion of albumin without altering its mRNA levels. Protein-labeling and pulse-chase experiments showed that a low BCAAs/AAAs ratio reduced the biosynthesis, whereas a high ratio accelerated intracellular decay of albumin. These results suggest that normalization of the BCAAs/AAAs ratio improves albumin synthesis while the excess ratio may induce the degradation of albumin in the cells.