Developmental changes in the expression of α-tocopherol transfer protein during the neonatal period of rat

It is well known that the cellular concentration of α-tocopherol (α-toc) is about l0-fold greater than that of γ-tocopherol (γ-toc) despite the ingestion of a large amount of γ-toc in the diet. Recently, this discrimination of tocopherol is considered to be attributed to α-tocopherol transfer protein (α-TTP) which binds to α-toc in preference to the other forms of tocopherol in the liver. In the present study, developmental changes in expression of α-TTP after birth were investigated using rats with respect to plasma changes of tocopherols. The expression of α-TPP in the neonatal rat liver, which was very low immediately after birth, increased steadily during the two weeks of life before weanling and reached the adult level at four weeks. During the suckling period, the plasma ratio of α-toc to y-toc linearly increased, because plasma α-toc which was low immediately after birth, increased rapidly during the period, while y-toc remained unchanged. The increase in the ratio seemed to correlate with the developmental expression of α-TPP in the liver during this period.