Imbalance of Vitamin B Factors

Abstract

Previous experiments (Richards, 1945) showed that excess of vitamin B, in a diet rather low in the vitamin B complex caused deficiency of another vitamin B factor, pyridoxin. The deficiency, which appeared to be accentuated by addition to the diet of calcium carbonate (chalk), became manifest during the lactation period, when the suckling young developed convulsive fits characteristic of pyridoxin deficiency. No evidence of the deficiency had been apparent during the growth of the young rats before mating. It was decided, therefore, to increase the intakes of vitamin B, and chalk still further, in order to find whether the resulting accentuation of the dietary imbalance would elicit obvious differences between the groups of animals during their growth. From this experiment arose the present series of investigations dealing mainly with the effect of pyridoxin on the thymus development of suckling rats, under conditions of pyridoxin deficiency induced by excessive amounts of vitamin B, in the diet.A short account of part of the present investigation was communicated to the Biochemical Society (Richards, 1946).Since the growth test with the increased intakes of vitamin B, and chalk still showed no obvious differences between the groups, the animals were mated to find whether these increases would accentuate the effects previously observed on breeding and lactation. While the breeding tests were in progress, Stoerk & Zucker (1944), who had fed young rats after weaning on diets lacking in one or other of four vitamin B factors, reported atrophy of the thymus after 4 weeks of experiment, the atrophy being greater when pyridoxin was lacking than when vitamin B, , riboflavin or pantothenic acid was absent. This suggested that the conditioned pyridoxin deficiency produced by excess of vitamin B, might have an effect on the development of the thymus gland in the stage before weaning. The thymus glands of the young rats in subsequent litters were accordingly weighed at weaning. When it became evident that pyridoxin had a marked effect in preventing atrophy of the thymus in the young rats, a further experiment was made to determine whether this effect was specific for pyridoxin, or whether a similar result would be obtained by the addition of any other single vitamin B factors to the diet, unbalanced by its excessive content of vitamin B, . The specificity of pyridoxin for thymus development in young rats after weaning was proved by Stoerk in a later paper (Stoerk, 1946).

Influence of the Extraction Rate of Flour on Conditioned Pyridoxin Deficiency in Rats

“…Neither of these does succeeded in rearing any young. This is in accordance with a previous finding (Richards, 1949) that does subject to fits appeared to be incapable of rearing their litters. Doe 24, which was about 4 months old when fits were first seen, litters (daily weighings).'…”

“…The values for the animals of the first generation show the low weights in group 72, in which the conditioned pyridoxin deficiency was most severe, and the tendency for the weights to increase with the rising rate of extraction of the flour. The low values in group 72 are in accordance with those previously found in pyridoxin-deficient animals (Richards, 1949). It is known that vitamin B-complex factors other than pyridoxin affect the development of the thymus after weaning, and the higher weights found in groups 77,80 and 85 may be due partly to the influence of increased amounts of these other factors, but the values found in group 72 plus pyridoxin suggest a specific effect of pyridoxin in promoting the development of the thymus before weaning.…”

“…This may possibly indicate a greater requirement of pyridoxin by the females during the period of rapid growth (cf. Richards, 1949). No definite reason can be given for the superior value for growth of shaded or unshaded, block in the vertical columns represents the average weight increase of a group for I week, the total increase for 8 wccks being shown at the top of the column.…”

“…Growth tests and breeding tests were carried out in the usual way (Richards, 1949), the young being weaned at 23 days of age.…”

The biological and therapeutic significance of organic phosphates occurring in nature

“…It is well known that deficiency symptoms connected with certain members of the B group of vitamins can be produced in animals (Richards, 1945(Richards, , 1949 if one other member is given in excessively large doses. Magyar & Gyorgy (1g49a, b) even go so far as to explain such deficiencies on the basis of an exhaustion of phosphorylating mechanism by over-utilization on the member present in excess, which thus becomes an unfair competitor.…”