Electrophoretic analysis of the sera of young rats

Abstract

The absorption of maternal antibodies by the gut of the young rat continues for 20 days after birth and then ceases abruptly. The sera of rats at different ages during and after the absorptive period were examined electrophoretically and ultracentrifugally to determine the changes in the serum proteins during this period. The serum protein of rats of all age groups contained two albumin components $\text{(albumin}_{1}$ $\text{and albumin}_{2})$ and four globulin components $(\alpha _{1}$-, $\alpha _{2}$-, $\beta $- $\text{and}$ $\gamma $-$\text{globulin}$, but the concentrations of these components, both relative and absolute, varied with age. The concentration of serum protein was considerably higher in mature than in suckling rats, due largely to a greater concentration of albumin. The amount of $\gamma $-globulin declined rapidly over the period 18 to 24 days of age, this decline paralleling that of the absorptive capacity of the gut of the young rat. The amount of $\beta $-globulin rose rapidly over this period. Conversely, between 24 and 40 days of age, the $\gamma $-globulin level rose and the $\beta $-globulin level declined. The changes in the $\alpha _{1}$- $\text{and}$ $\alpha _{2}$-globulin were less marked but both declined over the period 18 to 30 days of age.