Mechanism for the increased skeletal muscle protein degradation in the obese Zucker rat

Obese (fa/fa) Zucker rats showed a decreased protein content in skeletal mu scle compared with their lean counterparts, This was associated with both a decrease in the functional rate of protein synthesis and an enhanced fract ional rate of protein degradation in skeletal muscle, as studied by pre-loa ding body proteins with C-14-bicarbonate. The increased protein degradation could be the result of the clearly enhanced expression for several transcr ipts of the ubiquitin genes in skeletal muscle. The results suggest that th e increased protein degradation in the skeletal muscle of the obese animals may be due to increased activity of the ubiquitin-dependent proteolytic sy stem. (C) Elsevier Science Inc. 1999. All rights resented.