Enhancement of Vitamin B₁₂ Absorption by D-Sorbitol as Measured by Maternal and Fetal Tissue Levels in Pregnant Rats

Abstract

Tissue vitamin B 12 levels were determined in the blood, liver, kidneys, gastrointestinal tract and uteri and contents in pregnant and nonpregnant female rats following oral administration of three doses of radioactive vitamin B 12 (Co 60 ). Differences in radioactivity of tissues of animals administered Co 60 vitamin B 12 in water and in d-sorbitol at different stages of pregnancy were noted. d-Sorbitol administration significantly enhanced vitamin B 12 absorption in both pregnant and nonpregnant rats. Gestation, but not d-sorbitol, causes an alteration of the tissue distribution pattern of the vitamin. As fetal growth progressed the fetuses obtained a large proportion of the absorbed B 12 which would normally have gone to the maternal tissues. During growth of the total fetal mass from 3 to 30 gm the amount of B 12 retained per gram of tissue remained fairly constant. The amount of B 12 taken up by the fetuses was to a great degree controlled by the amount of the vitamin absorbed by or stored in the mother during gestation.