The Content of Vitamin B₁₂ in Adult and Foetal Tissue: A Comparative Study

Abstract

S ummary . The vitamin B 12 content of 17 tissues in 28 adults and 17 foetuses was measured by a Euglena gracilis bioassay. The former were taken after sudden deaths, many accidental, and the latter after therapeutic abortions for mild psychiatric reasons. In the adult, the liver had the highest level of vitamin B 12 followed by the kidney, adrenal, pancreas and heart. The tissues of greatest vitamin B 12 concentration in the foetus were the liver, adrenal, kidney and lung. Foetal spleen, lung and colon were significantly higher than their adult counterparts, while foetal liver, kidney, heart and brain were significantly lower in comparison with the adult. Differences in vitamin B 12 levels may reflect adult and foetal differences in circulation, metabolic maturity or plasma vitamin B 12 transport.