Endocrine myopathies

Other Inflammatory Muscle Disorders Endocrine Myopathies Thyroid Disorders Adrenal Disorders Pituitary Disorders Parathyroid Disorders Pancreatic Disorders Drug-Induced and Toxic Myopathies Management of Muscle Disease... 

To cover these various disorders in an orderly and comprehensive manner, the following sections are devoted, respectively, to the muscular dystrophies the congenital myopathies the metabolic myopathies the myotonias, periodic paralyses, and malignant hyperpyrexia the neurogenic disorders the inflammatory muscle disorders the endocrine myopathies and the drug-induced and toxic myopathies. 

Insulin is a powerful anabolic hormone but it is unlikely that insulin deficiency causes skeletal muscle atrophy by direct action on muscle fibers (as opposed to neurogenic atrophy) except in chronic untreated cases. There is however a close parallel between the catabolic states induced by glucocorticoid excess and by insulin deficiency. Moreover, impaired insulin action is implicated in other endocrine myopathies as a contributory cause of muscle wasting. Both acromegaly and thyrotoxicosis are associated with insulin resistance due to a postreceptor defect, and secondary hyperparathyroidism due to hypophosphatemia also gives rise to insulin insensitivity. 

Engel, A.G. (1988). Metabolic and endocrine myopathies. In Disorders of Voluntary Muscle (Walton. J.N., ed.), pp. 811-868, Churchill-Livingstone, Edinburgh. 

Myopathy is the term used broadly for affections of the skeletal musculature, in which the muscular symptoms in no way arise from disordered function of the central or peripheral nervous system. Within this definition are included, therefore, such widely differing conditions as the polymyositis syndrome, endocrine myopathies associated with thyroid gland disorders, and the muscular dystrophies. 

Category X) and lactation. The HMG-CoA reductase inhibitors are used cautiously in patients with a history of alcoholism, acute infection, hypotension, trauma, endocrine disorders, visual disturbances, and myopathy. 

Cathepsin L-deficient mice show decreased levels of enkephalin in the brain, with reduction by approximately one half (22). In addition, enkephalin brain levels are also reduced by about one half in PC2-deficient mice (28). These results support dual roles for both cathepsin L and PC2 in enkephalin production. Ongoing studies indicate multiple neuropeptides that are substantially decreased by more than 50% in the brain and endocrine tissues of cathepsin L knockout mice (Eunkelstein et al., submitted for publication). With the observed alterations in brain neuropeptides, it will be of interest in future studies to assess the behavioral effects of the loss of neuropeptides in cathepsin L knockout mice. Cathepsin L knockout mice are viable and show phenotypes of hair loss and cardiac myopathy (29, 30). The mechanism for these functional effects of cathepsin L deficiency could possibly involve neuropeptides. New and continued investigations of neuropeptides in cathepsin L knockout mice will provide knowledge of the relative roles of cathepsin L in the production of particular neuropeptides. 

Neuromuscular/Skeletal Myalgia/Myositis/Myopathy/Myotoxicity (2.6%) Endocrine/Metabolic Weight loss... 

Chambers FA+, Anaesthesia 47, 585 Central Nervous System Paresthesias (< I %) Neuromuscular/Skeletal Myalgia/Myositis/Myopathy/Myotoxicity (< 1%) Endocrine/Metabolic Gynecomastia... 

Myotonic dystrophy appears as a rather special case, since creatinuria is small or absent. In this disease it is thought that there is also a decrease in creatine synthesis, possibly due to an endocrine disturbance (see Zl). There is some indication that the same may be true of the hereditary myopathy in mice (P16). 

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