抄録
The circulating erythrocytes of Rana catesbeiana tadpole and adult frog were separated into young and old age fractions according to their density by use of the method of Danon et al., in which phthalate esters are used as a separating liquid, and also by use of Murphy's technique.
The density-separated tadpole and adult frog erythrocytes were subjected to measurements of [14C] leucine incorporating activity into hemoglobin and to differential determination of tadpole and adult frog hemoglobins with immunoprecipitation. Change-over from tadpole to adult frog erythrocytes during metamorphosis was investigated in relation to the transition of hemoglobin. The results obtained are as follows;
1) The tadpole and adult frog erythrocytes are distributed in the density ranging from 1.0850 to 1.1000 and from 1.0925 to 1.1075, respectively.
2) At the onset of metamorphosis, the tadpole erythrocytes become heavier.
3) At the metamorphic climax, the circulating erythrocytes are separated into two groups differing in their density from one another. The less dense cells contain the adult frog hemoglobin and are highly active to synthesize the hemoglobin molecule, whereas the more dense cells contain the tadpole hemoglobin and show a low biosynthetic activity.
4) The transition from tadpole to adult frog hemoglobin occurs in parallel with the changeover from tadpole to adult frog erythrocytes during metamorphosis.
