Protein metabolism in guanethidine-treated rats
| Autor: | Marcela Bielavská, Milan Holecek, L. Šprongl |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
medicine.medical_specialty
Glycogenolysis Catabolism Protein turnover Protein metabolism Skeletal muscle Cell Biology Biology medicine.disease Pathology and Forensic Medicine Cachexia Muscle hypertrophy chemistry.chemical_compound medicine.anatomical_structure Endocrinology chemistry Internal medicine medicine Molecular Biology Guanethidine medicine.drug |
| Zdroj: | International Journal of Experimental Pathology. 85:257-264 |
| ISSN: | 0959-9673 |
| DOI: | 10.1111/j.0959-9673.2004.00400.x |
| Popis: | The main functions of the adrenergic innervation in the body are to regulate the tone of smooth muscle of blood vessels, increase the performance of the heart and of the respiratory system and regulate the activity of several enzymes of carbohydrate and lipid metabolism (Guyton & Hall 1996). Activation of the sympathetic system and enhanced release of catecholamines to the blood stream are considered to be not only an important part of reactions in stress condition like exercise, but also a part of a complex of catabolic reactions related to the development of cachexia in stress illness, e.g. sepsis, trauma, surgery, haemorrhage or burn injury (Finley et al. 1986). As catecholamines promote the breakdown of both glycogen and fat, they are classified as ‘catabolic’ hormones. However, in several studies, it has been demonstrated that catecholamines have anabolic effect on protein metabolism, which is related to decreased proteolysis via stimulation of β2 receptors (Navegantes et al. 2000). Administration of β2-adrenergic agonists, e.g. clenbuterol or cimaterol, markedly stimulates hypertrophy of skeletal muscle and may be used in the treatment of atrophy of denervated muscle (Reeds et al. 1986; McElligott et al. 1987; Zeman et al. 1987; Kim & Sainz 1991). The beneficial effect of catecholamines on protein balance may also be applied in the treatment of muscle wasting caused by the systemic response of the body to cancer. Chance et al. (1991) and Costelli et al. (1995) demonstrated independently that muscle protein waste in tumour-bearing rats is effectively antagonized by clenbuterol. These observations indicate that catecholamines are not typical ‘catabolic’ hormones and that the adrenergic system has an exceptional position in regulating metabolic response of the body to various stimuli. Its stimulatory effects on lipolysis, glycogenolysis, blood circulation and oxidative reactions in mitochondria enable the body to provide by the sufficient amounts of energy for skeletal muscle, heart, nervous system, immune system and healing of injured tissues (Guyton & Hall 1996). The protein anabolic effect of catecholamines may reduce the protein wasting effect of a number of humoral factors whose production is activated in stress illness, particularly of cortisol and proinflammatory cytokines, e.g. interleukin-1 (IL-1), IL-6 and tumour necrosis factor. Unfortunately, the mechanism of protein anabolic effect of catecholamines is not fully understood. Particularly, there is a lack of data concerning their effect on protein synthesis, and if this effect is restricted only to skeletal muscle. The aim of the present study was to estimate the influence of short-term adrenergic blockade by guanethidine on the rate of whole-body protein turnover and on protein synthesis in specific tissues, i.e. in skeletal muscle, liver, small intestine, colon, spleen and kidneys. |
| Databáze: | OpenAIRE |
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