Messenger RNA levels of plasma proteins in rat liver during protein depletion and refeeding

Abstract

The levels of mRNA for albumin, transferrin, transthyretin, the beta-chain of fibrinogen and apolipoprotein E in livers from rats during protein depletion and refeeding were measured by hybridization to specific cDNA probes. A period of protein depletion of 3 d resulted in a 30-40% decrease in mRNA levels for all five proteins. These levels were further decreased by only 15-20% after additional protein depletion for 6 d. There was no noticeable change in mRNA levels within 4 h of refeeding by gavage with a casein hydrolysate suspension supplemented with L-tryptophan and L-arginine. Upon refeeding a 30% protein diet, mRNA levels returned to normal after 3 d. The work presented here suggests that changes observed in the protein synthetic rate following protein depletion and repletion are due to changes in mRNA levels altered as a consequence of the availability of dietary protein.