B VITAMIN DEFICIENCY STATES 427 



accompanying reduction of the accessory organs of reproduction and 

 decreased sexual behavior. In adult mice, vitamin B 6 deficiency results 

 in failure to maintain body weight, and death inside of two months. In 

 young mice there is a paralysis of the hind legs, but no dermatitis which is 

 frequently seen in the rat. In adult mice, however, the acute stages of 

 deficiency do show pathological skin manifestations and frequently 

 necrotic tails. 



There is no dermatitis in the apyridoxic chick, but growth is slow and 

 accompanied by anorexia and general signs of debility. Pigs and dogs 

 have also been studied with regard to vitamin B 6 deficiency and both 

 develop anemias. lso ' 1S1 In the pig the anemia is microcytic, the bone 

 marrow hyperplastic, and both it and the spleen and liver are siderotic 

 (contain excessive iron deposits). One of the most significant changes 

 seen in dogs, rats, chicks, and pigs during vitamin B 6 deficiency is the 

 typical epileptiform seizures. 182 The attack appears suddenly, the animal 

 running about wildly in great excitement, then falling and undergoing 

 both clonic and tonic convulsions, followed by coma and collapse. Slow, 

 confused recovery follows upon the rather brief period during which the 

 attack occurs. Nervous degeneration occurs in acute vitamin B 6 defi- 

 ciency, as in the case of the other B vitamins, and in the dog at least 

 there is pronounced cardiac hypertrophy. 



The epileptiform seizures seen in lower animals have been responsible 

 for the study of pyridoxine efficacy in human epilepsy. The results in 

 this regard, however, have not been promising. Davenport and Daven- 

 port 183 have shown that pyridoxine increases the electroshock threshold 

 of mildly apyridoxic rats, but not of normal animals. Glutamic acid 

 similarly increases the threshold, and tryptophan, which intensifies 

 vitamin B 6 deficiency, lowers it. In severe deficiency, pyridoxine causes 

 only a slow rise in the electroshock threshold unless there has been 

 previous loading with glutamic acid. These facts all tend to suggest that 

 maintenance of transaminase activity is critical for a high electroshock 

 threshold — a suggestion with many implications in the field of brain 

 metabolism and mental disease. 



Dairy cattle apparently develop a natural vitamin B 6 deficiency — a 

 fact that is remarkable both because of the resistance of ruminants to 

 avitaminoses, and the apparently rare occurrence of natural apyridoxosis. 

 In cattle the affliction is manifest by anorexia, thinness, a poor hair coat, 

 retarded growth, and most characteristic of all by a poikilocytosis. This 

 condition has been found to respond rapidly to pyridoxine administration, 

 and it will be of interest to see whether the corresponding poikilocytosis 

 in man (sickle cell anemia) bears any relationship to vitamin B 6 defi- 

 ciency. 184 In cobalt deficiency in sheep there is apparently a lowering of 



