Dermatitis in Pyridoxine-Deficient Rats

Abstract

Pyridoxine deficiency in rats has always been associated with a “specific dermatitis” which has been named acrodynia. 1 Dermatitis can be readily produced when thiamine and riboflavine are the only members of the Vitamin B complex fed. 2 , 3 While such a supplemented diet has often been referred to as a pyridoxine-deficient diet, it is deficient also in factor 2 or the filtrate factors. Factor 2 concentrates are now known to carry pantothenic acid plus other as yet unidentified filtrate factors. Addition of factor 2 will sometimes promote the development of dermatitis 4 and sometimes will give erratic results. 5

In this laboratory for a long time no dermatitis appeared on large numbers of pyridoxine-deficient rats, though the rats were obviously deficient since they either did not grow at all or grew slowly and responded spectacularly to pyridoxine administration. Because a good deal of dermatitis had been observed on pyridoxine-deficient rats in the past, the records were searched for changes in technic which might account for the absence of dermatitis on pyridoxine-deficient rats. The absence of dermatitis was found to be coincident with a change in technic involving feeding of supplements to the basal diet. In previous work, 21-day-old rats were put on the synthetic diet 4 without any addition of water-soluble vitamins for 10 to 12 days. Thiamine and riboflavine were then added for 14 days after which factor 2 concentrates 4 were added. A large proportion of these rats developed dermatitis. The change in technic consisted in feeding thiamine, riboflavine and factor 2 concentrates to the rats when they were put on the synthetic diet at 21 days of age without any depletion period.

Forty rats were accordingly put on the basal diet 4 for a depletion period of 12 days after which, for a period of 2 weeks, only thiamine and riboflavine were fed.