title: The effect of severe dietary protein restriction on skeletal muscle fiber number, area and composition in weanling rats.
abstract: The purpose of the present investigation was to determine the effects of severe dietary protein restriction on soleus (S) and tibialis anterior (TA) fiber number and S muscle fiber area, composition and length. The S and TA muscles were removed from one leg of 12 male Sprague-Dawley rats at 21 d of age. Six of these animals were placed on a 1% protein diet until 42 d of age, while six served as age-matched controls. Muscle fiber number was determined by the nitric acid digestion method for S muscles and the mean fiber dry-weight estimation method for the TA muscles. Mean fiber numbers for the S muscles were 2,655 +/- 42 and 2,669 +/- 71 for the treatment group at 21 and 42 d of age, respectively, and 15,989 +/- 899 and 16,067 +/- 695 at 21 and 42 d of age, respectively, for the TA muscle. For the age-matched control group, fiber numbers for the S muscle were 2,928 +/- 78 and 2,949 +/- 76 at 21 and 42 d, respectively, and 17,964 +/- 281 and 18,445 +/- 296 at 21 and 42 d, respectively, for the TA muscle. The S muscle fiber area, composition and length were studied using 12 male Sprague-Dawley rats. Six animals were placed on the 1% protein diet from 21 to 42 d of age, while six animals served as age-matched controls. The S muscle fiber area was 33.1 and 51.5% smaller for type I and type II fibers, respectively, for animals fed the 1% protein diet. The S fiber length was 27.9% less in animals fed the 1% protein.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D002452:Cell Count; D004044:Dietary Proteins / Q000008:administration & dosage*; D008297:Male; D009132:Muscles / Q000033:anatomy & histology / Q000166:cytology*; D009929:Organ Size; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D004044:Dietary Proteins