Metabolism of vitamin B/sub 12/ in the rat in pantothenic acid deficiency.

AMONG the various interrelationships between the members of the B group
of vitamins, perhaps the most interesting is that between pantothenic acid and
vitamin B12. Reports of elevations in hepatic concentration of coenzyme A in
vitamin B12 deficient animals (Boxer et al, 1953, 1955 ; Wong and Schweigert,
1956) have been closely followed by observations of increased stores of vitamin B12
in pantothenic acid-deficient rat livers (Radhakrishnamurthy and Sarma, 1957). This
reciprocal relationship between the two vitamins has since been confirmed by
several others (Moruzzi et al, 1958 ; Aiyar et al., 1959; Aiyar and Sreenivasan,
1961a). While studies in this laboratory have indicated that the elevation in
hepatic coenzyme A stores in vitamin B12 deficiency is due to alterations in the
sulfhydryl metabolism resulting in an increased channelling of sulfhydryl reserves
of the cell into coenzyme A, rather than into glutathione or methionine (Aiyar and
Sreenivasan, 1961a) the increase in liver concentration of vitamin B12 in pantothenic-
acid deficiency needs further investigation.
The present work relates to studies on the metabolism of vitamin B12 in
pantothenic acid-deficient rats. Observations on the alterations in liver and serum
levels of vitamin B12, as also in its urinary excretion, are presented and discussed.