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A morphological/biochemical study on the actions of corticosteroids on rat skeletal muscle
Author(s) -
Kelly Frank J.,
McGrath Josephine A.,
Goldspink David F.,
Cullen Michael J.
Publication year - 1986
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880090102
Subject(s) - endocrinology , medicine , anabolism , skeletal muscle , corticosteroid , hormone , atrophy , catabolism , biology , cortisone , glucocorticoid , chemistry , metabolism
Four corticosteroid hormones were administered (5 mg/kg/day) to rats over 6 to 10 days. Both biochemical and microscopic techniques were employed to determine the influence of these corticosteroids on the fine structure and growth of five striated muscles. Throughout, dexamethasone and triamcinalone were more potent than prednisone or cortisone in influencing muscle growth. The corticosteroids' action on the heart was anabolic, increasing its RNA and protein content. In contrast, the same corticosteroids were catabolic against fast‐twitch muscles (e.g., extensor digitorum longus), inducing appreciable atrophy. However, slow‐twitch muscles (e.g., soleus) were more resistant to these hormones, exhibiting an intermediate response between that of the heart and fast‐twitch muscles. Only minor morphological changes were found in both fast and slow muscles 10 days after the corticosteroid treatments. The hormones′ atrophic effects on skeletal muscle primarily arose from the corticosteroid's ability to inhibit protein synthesis, via decreases in the muscles′ ribosomal capacities. Whole‐body protein synthesis was also suppressed by these corticosteroids, but to a lesser extent than in the whole skeletal musculature.