Hepatic level of rat albumin messenger RNA is influenced by factors other than dietary protein.

Dot hybridization of messenger RNA (mRNA) and complementary DNA (cDNA) has been used to measure the relative levels of albumin and alpha-fetoprotein mRNA in liver of rats fed for 5 d a fat-free (carbohydrate-rich) diet, a high fat diet or a basal diet, all three of which were isonitrogenous. The level of albumin mRNA in rats fed the fat-free (carbohydrate-rich) diet was 30 to 45% of the level in animals fed the basal 4% fat diet. The concentration of another mRNA, that for alpha-fetoprotein, remained unchanged. It has been established by others that albumin mRNA levels and albumin synthesis are diminished in response to low levels of dietary protein. We show that albumin mRNA levels are lower than those observed in animals fed the basal 4% fat diet, even when dietary protein is adequate (30% wt/wt), if the nonprotein calories are derived solely from carbohydrate.