In vivo C14-L-alanine metabolism in rat dietary obesity induced by cafeteria diet.

The "in vivo" handling of L-alanine in 24 hours starved rats, in which obesity was induced by feeding with cafeteria diet, was compared with that of starved control rats. 14C-alanine was administered in trace amounts in order not to affect the normal handling of this amino acid. The results obtained in blood and liver support a lowered glucose formation from alanine. The specific radioactivities corresponding to lactate, glutamate + glutamine and asparagine as well as total protein and total lipid, were all lowered in the obese group. This strongly suggests that glucose formation from alanine in the liver was impaired. The specific radioactivity of the metabolites studied in the striated muscle are compatible with the above suggestion. It can be concluded that the glucose alanine cycle operation is inhibited in the cafeteria diet starved obese rats.