380 THE BIOCHEMISTRY OF B VITAMINS 



nourished populations, however, this factor seems adequately compen- 

 sated for by the increased appetite and consumption of other nutritional 

 materials. Except when specific factors make it seem expedient, there 

 consequently seems little justification for the B vitamin supplementation 

 of the diets of growing children. When however the practice is instituted, 

 supplementation of the diet with a variety of other important "nutritional 

 factors would also seem to be highly desirable. 



Endocrine Function and Reproduction. * The known interrelationships 

 between the B vitamins and endocrine function are numerous; 1 * 1 at our 

 present state of knowledge many are nebulous, but a few cases at least 

 have received considerable attention. The endocrine glands represent 

 areas of high metabolic activity, and it is logical to assume that they 

 would demonstrate unusual sensitivity to changes in vitamin balance for 

 that reason. They function, moreover, in a catalytic role frequently asso- 

 ciated with the control of specific metabolic processes, and the effects 

 produced by the superimposition of two catalytic factors would for 

 kinetic reasons be extremely pronounced. 



As mentioned earlier, B vitamin deficiency results in a pathological 

 condition of all the body tissues, and depleted glandular tissue will gen- 

 erally manifest such a condition by cytological changes and deranged 

 function. While such a condition is not always observed in all the en- 

 docrines, there seems ample evidence to indicate that it does occur in 

 those cases where other factors do not produce death before the effect 

 is observable. It is remarkable that relatively little is known about the 

 hypophysis in this regard, and this fact may be a reflection of special 

 preservative powers possessed by this key gland. In other cases, little is 

 known regarding vitamin interrelationships aside from the natural de- 

 generative changes occurring in deficiency. Certain special relationships 

 are known, however, that seem to involve more than this, and it is with 

 these that our concern here rests. They involve primarily the thyroids, 

 the adrenal cortex, and the gonads. Were our knowledge adequate, it 

 would of course be apparent that these relationships extend through these 

 endocrines to the others. 



Thyroid relationships. The thyroid gland exerts its effects by virtue 

 of its relationship to the metabolic rate, which in turn has a profound 

 influence on B vitamin requirements. There is seldom any pronounced 

 thyroid change in B vitamin deficiency states. Experimental hyper- 

 thyroidism in animals produces a number of characteristic changes — loss 

 of weight, interrupted sexual cycles, hepatic damage, cardiovascular dis- 

 orders, and a drop in liver glycogen. These symptoms can for the most 



* The function of the B vitamins as plant hormones has been discussed earlier 

 (p. 316), and has recently been thoroughly reviewed in the literature (1). 



