600 BIOTIN 



X. Effects of Deficiency 



PAUL GYORGY 



A. RATS AND MICE 



Egg white injury as a clinical manifestation of biotin deficiency was 

 first produced in rats, and until the present time rats have been the pre- 

 ferred experimental animals for the study of this deficiency. As stated in 

 previous sections biotin deficiency produced by feeding raw or unheated 

 commercial egg white to rats is characterized by a progressive dermatitis 

 ( see Figs. 5-7), reminiscent of scalj^ desquamative dermatoses of the sebor- 

 rheic type.'"^ 



The initial symptom of a progressive disturl^ance of the skin in rats is a 

 dermatitis which is at first confined to the groin and the genitalia and to 

 the neck and around the snout. In the later stage of the disease in rats, 

 brown, adherent scales of varying size and thickness, together with pro- 

 gressive alopecia, become apparent in and around the inflamed areas. As a 

 rule, neither the dermatitis nor the alopecia in these rats has well-defined 

 borders. Often small, thin, almost point-like but also confluent, brown pig- 

 mented scales appear, usually confined to the back and not necessarily 

 accompanied by severe dermatitis or alopecia, although both may be pres- 

 ent simultaneously with erythematous lesions. ^"^ The region round the 

 mouth is usually very severely affected. In some instances skin hemorrhages 

 and edema, especially of the feet, appear.^' ^ In mild cases the skin lesions 

 may be limited to alopecia around the eyes: "spectacle eye condition."^ 



In exceptional cases the disease may involve the skin of the whole body 

 of the rat and may resemble the typical exfoliati\'e dermatitis seen in adults 

 or Leiner's disease (erythroderma desquamativum), its counterpart in in- 

 fants. The epidermis of the rat is shed in large or small thin scales, (see Fig. 

 8), which on account of their rapid and continuous ])roduction become 

 colorless and devoid of fat, the brown color and the high fat content being 

 confined to the first, long adherent scales. Because of blepharitis, the eye- 

 lids often stick together and are covered with yellow scales, (leneralized 

 alopecia and prui'itus are often observed. In black or piebald rats dei)ig- 

 mentation of the fur becomes noticeable, and the black hair turns biownish 



1 P. Gyoi-fry, Z. drztl ForlhihI. 28, ;^77. 417 (1931). 



2 P. Gyorjfy, in Haii(ll)U('li (1(m- Iviiulci-licilkuiulo, 4tli eil.. Cliaptcr 10, p. 4o. F. C. W. 

 Vogel, Berlin, 1035. 



3 P. Gyorgy, Arch. Dermatol, and Si/phit,)!. 43, 230 (li»41). 

 ' M. A. Boas, Biochem. J. 21, 712 (1027). 



^ n. T. Parsons, /. Biol. Chem. 90, 3r)l (1031). 



6 W. D. Salmon and J. G. Goodman, ./. Xulritiun 8. 1 (1034). 



7 E. Nielsen and C. A. Elvchjcm, Proc. Soc. Exptl. Biol. Mnl. 48. 310 0041). 



