Developmental and convalescent changes of the anemia caused by excess methionine in the rat

An experiment was performed to investigate the progressive changes of the anemia caused by excess methionine in rats, during the developmental and convalescent periods. Hemoglobin concentration, hematocrit value and red blood cell count were elevated in the initial stage of excess methionine feeding, they then gradually decreased. During the convalescent period, after ceasing administration of the excess methionine diet, symptoms of anemia gradually disappeared. The nitrogen efficiency ratio was markedly decreased by excess methionine feeding, however, it rapidly recovered after ceasing administration of the excess methionine diet. Iron deposited in the spleen also disappeared quickly during the convalescent period. Of the symptoms of anemia caused by excess methionine, the activity of delta-aminolevulinic acid synthetase (ALAS) in the bone marrow showed the most acute changes. As mentioned previously (1), although lowered globin biosynthesis due to amino acid imbalance could be considered as one of the important causes of the anemia and also would be one of the causes of the compensative elevation of ALAS activity, the possibility still remain that there are other unknown effects of excess methionine on ALAS activity in the bone marrow in this case.