Enzyme-deficient mice are less fat

Penxiang She, Sarah Bronson, Thomas Vary, Andras Hanjal and Christopher Lynch of Penn State College of Medicine, together with collaborators from Wake Forest University, have discovered that mice whose BCATm gene is disrupted are leaner than normal mice.

The gene encodes an enzyme that catalyzes the first step in the metabolism of branched-chain amino acids. Compared with wild-type mice, mice lacking the enzyme:

• ate more but were leaner
• had improved insulin sensitivity and glucose tolerance
• were more resistant to obesity induced by a high-fat diet

The enzyme-deficient mice burned significantly more calories than the wild-type mice, apparently because of increased protein turnover in a "futile" cycle of protein synthesis and degradation.

The researchers describe their findings in a paper in Cell Metabolism.

More about this research, and its implications, from Penn State Live.