522 the tocopherols 



4. Muscular System 

 a. Skeletal Muscle 



Nutritional muscular dystrophy constitutes the most universal manifes- 

 tation of vitamin E deficiency (Table II) and signifies a vitally important, 

 but as yet unknown, function of tocopherol in the metabolism of skeletal 

 muscle. Although the histopathologic changes vary considerably from spe- 

 cies to species, and even at different age periods in the same species, there 

 is still a fundamental pattern of change which is expressed as an acute 

 type of reaction in young animals and as a chronic type in adult animals. 

 The former type, of which the "late lactation" paralysis of rats is typical, 

 has received most attention because of ease of production experimentally 

 and occasional spontaneous occurrence in domestic animals. Since com- 

 bined placental and mammary transfer of tocopherol is often barely suffi- 

 cient to meet the daily needs of the young offspring of mammals, inade- 

 quacy of dietary tocopherol during the lactation and early post-lactation 

 periods, when there is unusually rapid growth and maturation of muscle 

 fibers, can be expected to have a particularly devastating effect. The dys- 

 trophic changes occuring in adult animals bear a close resemblance to the 

 lesions of human muscular dystrophy and to the hyaline necrosis (Zenk- 

 er's degeneration) of muscle which follows prolonged febrile states, such 

 as typhoid fever in man. It should also be kept in mind that at any given 

 stage of vitamin E depletion there are certain differences in the extent to 

 which the dystrophic process affects different muscles in the same animal, 

 or even different regions of any one muscle. 



(1) Late-Lactation Paralysis. When vitamin E I'eserves of lactating rats 

 are critically low, the suckling young frequently exhibit a generalized paral- 

 ysis, usually between the 18th and 25th days of life.^" This often appears 

 rather suddenly. There is clenching of the forepaws, weakness and drag- 

 ging of the extremities, inability to recover posture when placed on their 

 backs, diminution of respiration and body temperature, listlessness and 

 death. Spontaneous recovery may occur when symptoms are mild. Vitamin 

 E therapy prevents the symptoms if given as late as the 15th day of lacta- 

 tion, but it has little or no beneficial effect once symptoms have appeared. 

 Spontaneous recovery with retention of residual paralysis has been ob- 

 served,^"- ^^ but it is of rare occurrence. Lesions of the brain and spinal 

 cord have been described^^- ^^^ but not confirmed. Most investigators favor a 

 purely myogenic origin of the dystrophic process. Immobilization of a 

 muscle by section of its nerve or its tendon prior to the 18th day markedly 



6» H. M. Evans and G. O. Burr, /. Biol. Chem. 76, 273 (1928). 

 " H. M. Evans, J. Mt. Sinai Hosp. N. Y. 6, 233 (1940). 

 " M. D. Lipshutz, Rev. Neurol. 65, 221 (1936). 

 62a W. de Gutierrez -Mahoney, Southern Med. J. 34, 389 (1941). 



