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

Abstract

Tissue vitamin B12 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 B12 (Co60). Differences in radioactivity of tissues of animals administered Co60 vitamin B12 in water and in d-sorbitol at different stages of pregnancy were noted. d-Sorbitol administration significantly enhanced vitamin B12 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 B12 which would normally have gone to the maternal tissues. During growth of the total fetal mass from 3 to 30 gm the amount of B12 retained per gram of tissue remained fairly constant. The amount of B12 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.

VITAMIN B12Co60 READILY PASSES THE PLACENTA INTO FETAL ORGANS AND NURSING PROVIDES B12 FROM MOTHER TO PUP

“…Grasbeck et al (6) also conclude that there is an enterohepatic circulation of B1,. Numerous reports have been written indicating the passage of Ba~Co 6° through the placenta (8,5,11,3), but none has gone into the extensive detail of placental and nursing transfer with the final distribution of the radioactive material in the pups. 1082 4045 6130 1378 1175 1460 2669 3140 528 1549 511 1249 800 4880 2185 1234 1900 3160 3081 332 1769 588 790 1091 1652 4945 1522 770 1512 1263 2111 199 2042 771 982 1432 2311 4430 1768 909 1260 1970 2579 1045 1465 1370 4140 5181 2075 969 2260 2181 3165 450 Dog 57-372.…”

“…Numerous reports have been written indicating the passage of Ba~Co 6° through the placenta (8,5,11,3), but none has gone into the extensive detail of placental and nursing transfer with the final distribution of the radioactive material in the pups. In studies of human beings, it has been demonstrated that serum BI, levels are low in the mother with increased amounts in the fetus (2,7).…”