Alterations in rat serum proteins in relation to dietary proteins and B vitamins. I. Studies with growing rats

Abstract

The alterations in rat serum proteins resulting from (i) variations in dietary protein quality and level, (ii) minimal intakes of B vitamins and (iii) single and combined deficiencies of vitamin B₁₂ and folic acid have been studied with egg albumin, casein and peanut protein diets at 10 and 18 per cent. protein levels. Protein quality chiefly influences serum concentrations of albumin and α₁-globulin, the effects on other fractions being variable. Protein level affects serum levels of albumin, α₁-globulin and α₂-globulin. The effects due to these dietary variables are interdependent. Variations in dietary protein quality do not alter the relative distribution of serum protein fractions. Changes in protein level cause shifts in the relative distribution of globulins, the albumin-globulin ratio remaining unaltered. The nature and extent of changes in serum protein profile due to vitamin insufficiencies or deficiencies are also influenced, qualitatively and quantitatively, by dietary amino acids. With minimal intakes of B vitamins γ-globulin is chiefly reduced, but other fractions, particularly α₁-globulin, may also be affected. In a combined deficiency of vitamin B₁₂ and folic acid a common reduction in γ-globulin is variably attended by reductions in albumin and in α₁- and β-globulins. In single vitamin B₁₂ deficiency, the changes are confined to albumin, α₁-globulin and α₂-globulin fractions, whereas single folic acid deficiency chiefly affects γ-globulin with variable effects on albumin and β-globulin fractions.