Adaptations of muscular biology in response to potential glucocorticoid treatment in broiler chicken (original) (raw)
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The regulation of muscle mass by endogenous glucocorticoids
Frontiers in Physiology, 2015
Glucocorticoids are highly conserved fundamental regulators of energy homeostasis. In response to stress in the form of perceived danger or acute inflammation, glucocorticoids are released from the adrenal gland, rapidly mobilizing energy from carbohydrate, fat and protein stores. In the case of inflammation, mobilized protein is critical for the rapid synthesis of acute phase reactants and an efficient immune response to infection. While adaptive in response to infection, chronic mobilization can lead to a profound depletion of energy stores. Skeletal muscle represents the major body store of protein, and can become substantially atrophied under conditions of chronic inflammation. Glucocorticoids elicit the atrophy of muscle by increasing the rate of protein degradation by the ubiquitin-proteasome system and autophagy lysosome system. Protein synthesis is also suppressed at the level of translational initiation, preventing the production of new myofibrillar protein. Glucocorticoids also antagonize the action of anabolic regulators such as insulin further exacerbating the loss of protein and muscle mass. The loss of muscle mass in the context of chronic disease is a key feature of cachexia and contributes substantially to morbidity and mortality. A growing body of evidence demonstrates that glucocorticoid signaling is a common mediator of wasting, irrespective of the underlying initiator or disease state. This review will highlight fundamental mechanisms of glucocorticoid signaling and detail the mechanisms of glucocorticoid-induced muscle atrophy. Additionally, the evidence for glucocorticoids as a driver of muscle wasting in numerous disease states will be discussed. Given the burden of wasting diseases and the nodal nature of glucocorticoid signaling, effective anti-glucocorticoid therapy would be a valuable clinical tool. Therefore, the progress and potential pitfalls in the development of glucocorticoid antagonists for muscle wasting will be discussed.
Medycyna Weterynaryjna
The increasing production potential of birds is correlated with a lower health and immune potential, resulting in the appearance of numerous meat quality defects. The greatest concern for gallinaceous poultry (chickens and turkeys) is PSE meat, which is characterized by light colour, soft texture and a reduced water-binding capacity. The aim of the study was to compare plasma corticosterone concentration, muscle fibre diameter, and the apoptotic markers between normal and pale, soft, exudative (PSE) turkey breast muscles. The results show, that the PSE group is characterized by a significantly higher plasma corticosterone concentration and a significantly greater muscle fibre diameter at 30 min post mortem compared to the normal group. The time of refrigerated storage (4°C) of meat contributes significantly to reducing muscle fibre diameter in the PSE group at 24 h post mortem compared to 30 min post mortem. Additionally, the results obtain showed that the caspase-3 activity at 30 m...
Effect of glucocorticoid excess on skeletal muscle and heart protein synthesis in adult and old rats
British Journal of Nutrition, 1998
This study was carried out to analyse glucocorticoid-induced muscle wasting and subsequent recovery in adult (6-8 months) and old (18-24 months) rats because the increased incidence of various disease states results in hypersecretion of glucocorticoids in ageing. Adult and old rats received dexamethasone in their drinking water for 5 or 6 d and were then allowed to recover for 3 or 7 d. As dexamethasone decreased food intake, all groups were pair-fed to dexamethasonetreated old rats (i.e. the group that had the lowest food intake). At the end of the treatment, adult and old rats showed significant increases in blood glucose and plasma insulin concentrations. This increase disappeared during the recovery period. Protein synthesis of different muscles was assessed in vivo by a flooding dose of [13C]valine injected subcutaneously 50 min before slaughter. Dexamethasone induced a significant decrease in protein synthesis in fast-twitch glycolytic and oxidative glycolytic muscles (gastroc...
The Journal of Steroid Biochemistry and Molecular Biology, 1991
The concentration of the cytosolic glucocorticoid receptor (GR) was determined in skeletal muscles of calves in order to study possible differences in individual muscles from different parts of the body as well as the influence of sex and breed. In male and female Simmental calves the topographical distribution of GR was similar: the lowest concentrations were seen in abdominal muscle, whereas in neck, shoulder and hindleg the GR concentrations were higher; this difference was more pronounced in male than in female calves. In general, female calves had about 2-fold higher GR concentrations than males. The cytosolic cortisol concentrations were differing neither between individual muscles nor between sexes. The cortisol secretion during a 24-h sampling period 1 week prior to slaughter showed no sex difference. GR concentrations in neck muscle of female calves of four different German cattle breeds (Holstein Friesian, Brown Swiss, Simmental and German Gelbvieh) were rather similar; however, when Brown Swiss with the highest GR levels were compared to Holstein Friesian calves with the lowest concentrations, a significant difference was evident (P < 0.05).
Nutrition Research, 2003
The effects of macronutrient composition of the diet and glucocorticoid administration on weight gain, intestinal absorption and plasma lipids were investigated. Thirty seven male Wistar rats were divided into 4 groups, implanted with pellets continuously delivering either prednisolone (0.25mg/ day) or placebo and fed two isocaloric diets providing either high fat (HF: 50% of energy) or high carbohydrate (HC: 70% of energy). The four groups [group I (HC, placebo), group II (HC, prednisolone), group III (HF, placebo), group IV (HF, prednisolone)] were pair fed and given the mean amount of food eaten by the group with the least amount of energy intake on the previous day. After 4 weeks, the animals were sacrificed and serum glucose, total cholesterol (TC), HDL-cholesterol (HDL) and triglycerides (TG) were measured. All groups showed a decrease in relative intestinal absorption with time. Prednisolone-treated groups revealed significantly lower intestinal absorption. However, prednisolone-treated high-carbohydrate (HC) fed rats showed significantly higher weight gain, concomitant with a significant increase in feed efficiency. The HC diet induced a statistically significant increase in TG concentration. The results show that prednisolone treatment induces more weight gain on a HC as compared to a high fat (HF) diet possibly through a rise in feed efficiency.
Comparative Biochemistry and Physiology Part A: Physiology, 1993
Immature male Japanese quail received repeated (chronic) injections of 0.8 I.U. corticotrophin (ACTH), 0.1 mg or 1 .O mg ~o~i~osterone (B), or 0.02 mg dexametha~ne (DXM) and were fasted then refed at the end of the treatment period. A subgroup of the DXM group were given a single (acute) injection of 0.8 I.U. ACTH or saline before refeeding. A further group that had been given repeated injections of saline were fasted at the end of the treatment period. 2. All chronic hormone treatments decreased the rate of body weight gain and increased food consumption. Only the higher dose of B increased the lipid content of the carcass. This treatment and DXM also decreased the non-fat content of the carcass. 3. Plasma glucose and free fatty acids (FFA) were not altered by the chronic hormone treatments except DXM which increased plasma FFA. Acute injections of ACTH increased levels of plasma FFA and glucose in both controls and DXM-treated quails. Plasma glucose, but not FFA, was decreased by fasting. 4. De now hepatic fatty acid synthesis in oitro was unaffected by the chronic treatments, whilst acute injections of ACTH or fasting decreased it. The endogenous release of glucocorticoids as a result of food shortage, starvation and other stressors, and the resulting catabolic effects are well documented (Cahill, 1971; Chester Jones et al., 1972; Loeb, 1976). The catabolic effects of glucocorticoids such as growth suppression and muscle wastage have been mimicked experimentally in the domestic fowl and rat (
Impaired development of broiler chickens by stress mimicked by corticosterone exposure
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2006
The effects of corticosterone (CORT) administration on the development of muscular tissues of broiler chickens (Gallus gallus domesticus) fed with diets differing in lipid content were investigated. The experimental chickens were given one of two experimental diets: high lipid diet (9.9% crude fat) or control diet, from 21 d of age. At 28 d of age, half of the chickens in each dietary treatment were exposed to CORT treatment, supplemented with 30 mg CORT/kg diet for 12 days, while the other half continued to consume the former diet. The zootechnical parameters were recorded at 21, 28, 35 and 39 d, and a blood sample was obtained from 8 birds of each group, respectively. The growth performance of broiler chickens was significantly depressed by CORT administration, but not by dietary treatment. Corticosterone treatment resulted in enhanced energy expenditure. The results indicate that the development of breast muscle was more susceptible to stress mimicked by CORT administration. The results suggest that corticosterone administration enhanced hepatic fatty acid synthesis and resulted in the redistribution of energy to abdominal store from peripheral tissues. Diet rich in lipid content was favorable to the central fat deposit in stressed broiler chickens.
Quantitative and qualitative adaptations of muscle fibers to glucocorticoids
Muscle & Nerve, 2015
Introduction: The aim of this study was to investigate the effects of shortterm glucocorticoid administration in healthy subjects. Methods: Five healthy men received dexamethasone (8 mg/d) for 7 days. Vastus lateralis muscle biopsy and knee extension torque measurement were performed before and after administration. A large number of individual muscle fibers were dissected from the biopsy samples (preadministration: n=165; post-administration: n=177). Results: Maximal knee extension torque increased after administration (~13%), while both type 1 and type 2A fibers had decreased cross sectional area (type 1: ~11%, type 2A: ~17%), myosin loss (type 1: ~18%, type 2As: ~32%), and loss of specific force (type 1: ~24%, type 2A: ~33%), which was preferential for fast fibers. Discussion: Short-term dexamethasone administration in healthy subjects elicits quantitative and qualitative adaptations of muscle fibers that precede (and may predict) the clinical appearance of myopathy in glucocorticoid-treated subjects.
Limited resistance of hypertrophied skeletal muscle to glucocorticoids
Journal of steroid biochemistry, 1986
Male hypophysectomized rats were initially assigned to a control or an overloaded group that underwent compensatory hypertrophy of plantaris muscles to steady-state levels following removal of synergistic musculature. Plantaris muscle mass of overloaded animals was higher than that of controls by 38% (391 +/- 8 vs 284 +/- 7 mg) and glucocorticoid cytosol specific binding concentrations, using [3H]triamcinolone acetonide (TA) as the labeled steroid, was also significantly higher in hypertrophied muscles (83.3 +/- 3.9 fmol . mg protein-1) than in control muscles 56.3 +/- 3.9 fmol . mg protein-1). Cortisone acetate (CA) was then administered daily subcutaneously in high, 100 mg; intermediate, 10 mg; or low, 1.0 mg . kg-1 body wt doses. Groups of rats were killed after 1/4, 2 days and 7 days. Absolute muscle mass losses after 7 days of CA treatment were approx 80 mg with high doses and 60 mg with intermediate doses in both hypertrophied and control muscles. The low CA dose did not produ...