• Asian-Australasian Journal of Animal Sciences
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• v.22 no.2
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• pp.275-281
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• 2009

Modification of thyroid hormone levels has a profound effect on skeletal muscle differentiation, predominantly through direct regulation involving thyroid hormone receptors. Nevertheless, little is known about the regulation of myostatin gene expression in skeletal muscle due to altered concentrations of thyroid hormone. Thus, the goal of our study was to find out whether altered thyroid states could change the gene expression of myostatin, the most powerful inhibitor of skeletal muscle development. A hyperthyroid state was induced in rats by daily injections of L-thyroxine 20 mg/100 g body weight for 14 days, while a hypothyroid state was induced in another group of rats by administering methimazole (0.04%) in drinking water for 14 days. After a period of 14 days of L-thyroxine treatment we observed a significant increase of myostatin expression both in mRNA and protein level. However, decreased expression of myostatin mRNA and protein were observed in hypothyroid rats. Furthermore, our studies demonstrated that the upregulation of myostatin gene expression might be responsible for the loss of body weight induced by altered thyroid hormone levels. We concluded that myostatin played a role in a metabolic process in muscle that was regulated by thyroid hormone.

• Journal of the Korea Convergence Society
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• v.7 no.3
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• pp.185-193
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• 2016

The purpose of this study was to analyze the effects of combined exercise on body composition, funtional fitness and muscle protein synthesis related hormone in sarcopenic obesity elderly women. The subjects for the study were 20 obesity elderly women over 65 years old. They were divided into two groups, the sarcopenic obesity group(n=10) and non-sarcopenic obesity group(n=10). The variables of body composition and cardiovascular fitness were measured in all the subjects before and after 12-week combined exercise. The findings of this study were as follows; In the sarcopenic obesity elderly women (SG), % body fat significantly decreased in the SG group, FFM and ASM significantly increased. In the chair stand test and arm curl test, SG group significantly increased. SG group significantly changed in chair sit-and-reach test, back scratch test, 2-minute step test. In the muscle protein synthesis related hormone(growth hormone and IGF-1), SG group significantly increased.

• Journal of Nutrition and Health
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• v.29 no.8
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• pp.874-880
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• 1996

The effects of an anabolic steroid, nandrolone phenylpropionate(NPP), on body weight gain and body protein, and muscle protein metabolism were inestigated in adrenocorticotrophic hormone(ACTH)-treated male and female rats. Daily injections of 100ug/day of ACTH for 7-8 days caused a cessation of growth in females and a net loss of body weight in males which were associated with significant reductions in body protein content. However, food intake was not affected by ACTH in either sex. The weight, protein content and fractional rate of protein synthesis, measured in vivo, of gastrocnemius muscle were all significantly reduced in both sexes. NPP at a dose of 4mg/kg body weight prevented the reduction in body weight gain in ACTH-treate females but not in males. However, boy protein content was increased by NPP in both sexes which was associated with increases in the weight, protein content and fractional rate of protein synthesis of gastrocnemius muscle. ACTH treatment caused a marked increase in plasma concentrations of corticosterone in both sexes. NPP suppressed much of the increases in corticosterone concentrations in both sexes. The results of the present study suggest that NPP exerts at least part of its anabolic effect by reducing plasma concentrations of catabolic glucocorticoid hormones, through suppressing the response of the adrenals to ACTH.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.187-195
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• 2023

Sarcopenia is a phenomenon in which muscle function, including muscle strength, deteriorates as muscle mass decreases in the process of increasing age. The diagnosis of sarcopenia utilizes total muscle mass and limb muscle mass, and limb muscle mass is expressed as height squared, body weight, and BMI. Each divided value is used as an index, mainly less than 7.23 kg/m2 for men and less than 5.67 kg/m2 for women. Grip strength, standing up from a chair, and walking speed were mainly used as physical function factors, and grip strength less than 27 kg for men and less than 16 kg for women were used as indicators. The limb muscle mass showed a decreasing trend after peaking in the mid-20s in men, and maintaining a gradual peak in women from the mid-20s to the mid-40s, showing a more rapid decline in men. The rate of decrease in muscle mass and strength continues to increase after the age of 20, and muscle strength rapidly decreases after the age of 80. In Korean men, total muscle mass and limb muscle mass show a decreasing trend from the mid-30s, and a more markedly rapid decrease from the age of 60. For women, it remains constant from the age of 30 to the age of 50, then gradually decreases after the mid-50s, and shows a rather rapid decrease after the mid-70s, showing a more gradual decrease than that of men. Men show a sharp decrease from the mid-40s when limb muscle mass is divided by height squared, and women show a marked decrease after 70 years old when limb muscle mass is divided by height squared. Exercise for the prevention and treatment of sarcopenia results in an increase in protein assimilation hormone, an increase in antioxidant activity, a decrease in inflammation, an increase in muscle insulin sensitivity, and an increase in protein synthesis. Resistance exercise is basically used, and aerobic exercise and equilibrium A combination of exercises is effective. In addition, for a more efficient effect of sarcopenia through resistance exercise, it is necessary to supplement nutrition including protein.

• Journal of Pharmacopuncture
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• v.20 no.4
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• pp.235-242
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• 2017

Irisin is a novel hormone like polypeptide that is cleaved and secreted by an unknown protease from fibronectin type III domain-containing protein 5 (FNDC5), a membrane-spanning protein and which is highly expressed in skeletal muscle, heart, adipose tissue, and liver. Since its discovery in 2012, it has been the subject of many researches due to its potent physiological role. It is believed that understanding irisin's function may be the key to comprehend many diseases and their development. Irisin is a myokine that leads to increased energy expenditure by stimulating the 'browning' of white adipose tissue. In the first description of this hormone, increased levels of circulating irisin, which is cleaved from its precursor fibronectin type III domain-containing protein 5, were associated with improved glucose homeostasis by reducing insulin resistance. Irisin is a powerful messenger, sending the signal to determine the function of specific cells, like skeletal muscle, liver, pancreas, heart, fat and the brain. The action of irisin on different targeted tissues or organs in human being has revealed its physiological functions for promoting health or executing the regulation of variety of metabolic diseases. Numerous studies focus on the association of irisin with metabolic diseases which has gained great interest as a potential new target to combat type 2 diabetes mellitus and insulin resistance. Irisin is found to improve insulin resistance and type 2 diabetes by increasing sensitization of the insulin receptor in skeletal muscle and heart by improving hepatic glucose and lipid metabolism, promoting pancreatic ${\beta}$ cell functions, and transforming white adipose tissue to brown adipose tissue. This review is a thoughtful attempt to summarize the current knowledge of irisin and its effective role in mediating metabolic dysfunctions in insulin resistance and type 2 diabetes mellitus.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.8
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• pp.1187-1193
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• 2015

This study determined the effects of dietary restriction on growth and the expression of lipid metabolism and growth hormone signaling genes in the longissimus dorsi muscle (LM) of Korean cattle. Thirty-one Korean cattle steers (average age 10.5 months) were allocated to normal (N; n = 16) or dietary restriction (DR; n = 15) groups. The feeding trial consisted of two stages: for the 8-month growing period, the DR group was fed 80% of the food intake of the normal diet, and for the 6-month growth-finishing period, the DR group was fed a DR total mixed ration with 78.4% of the crude protein and 64% of the net energy for gain of the normal diet. The LM was biopsied 5 months (period 1 [P1] at 15.5 months of age) and 14 months (period 2 [P2] at 24.5 months of age) after the start of feeding. The mRNA levels were determined using real-time polymerase chain reaction. Body weight, daily feed intake, average daily gain, and feed efficiency were lower in the DR group compared with the normal group at both P1 and P2. At P1, the lipogenic fatty acid synthase (FASN) mRNA levels were lower (p<0.05) in the DR group compared with the normal group. The DR group tended (p = 0.06) to have higher of levels of growth hormone receptor (GHR) mRNA than the normal group. At P2, the DR group tended to have lower (p = 0.06) androgen receptor (AR) mRNA levels than the normal group. In conclusion, our results demonstrate that dietary restriction partially decreases the transcription of lipogenic FASN and growth hormone signaling AR genes, but increases transcription of the GHR gene. These changes in gene transcription might affect body fat accumulation and the growth of the animals.

• BMB Reports
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• v.48 no.9
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• pp.501-506
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• 2015

Based on the potential beneficial effects of growth hormone releasing peptide (GHRP)-6 on muscle functions, a newly synthesized GHRP-6-biotin conjugate was tested on cultured myoblast cells. Increased expression of myogenic marker proteins was observed in GHRP-6-biotin conjugate-treated cells. Additionally, increased expression levels of insulin-like growth factor-1 and collagen type I were observed. Furthermore, GHRP-6-biotin conjugate-treated cells showed increased metabolic activity, as indicated by increased concentrations of energy metabolites, such as ATP and lactate, and increased enzymatic activity of lactate dehydrogenase and creatine kinase. Finally, binding protein analysis suggested few candidate proteins, including desmin, actin, and zinc finger protein 691 as potential targets for GHRP6-biotin conjugate action. These results suggest that the newly synthesized GHRP-6-biotin conjugate has myogenic stimulating activity through, at least in part, by stimulating collagen type I synthesis and several key proteins. Practical applications of the GHRP-6-biotin conjugate could include improving muscle condition. [BMB Reports 2015; 48(9): 501-506]

• Journal of Integrative Natural Science
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• v.10 no.2
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• pp.74-77
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• 2017

Bradykinin receptor B2 (B2R) is a GPCR protein which binds with the inflammatory mediator hormone bradkynin. Kallidin, a decapeptide, also signals through this receptor. B2R is crucial in the cross-talk between renin-angiotensin system (RAS) and the kinin-kallikrein system (KKS) and in many processes including vasodilation, edema, smooth muscle spasm and pain fiber stimulation. Thus the structural study of the receptor becomes important. We have predicted the peptide structures of Bradykinin and Kallidin from their amino acid sequences and the structures were docked with the receptor structure. The results obtained from protein-protein docking could be helpful in studying the B2R structural features and in the pathophysiology in various diseases related to it.

• Fisheries and Aquatic Sciences
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• v.25 no.11
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• pp.572-578
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• 2022

An organism's physiological processes and behaviors are regulated by neuropeptides and hormone peptides. The first neuropeptide identified from echinoderms is SALMFamide. The two most well-studied SALMFamide neuropeptides are S1 and S2, which possess myoactivity on apical muscle, tube feet, and the cardiac stomach of starfishes. However, neuropeptide candidates identified from SALMFamide's precursor protein sequence have not been investigated. This study aims to compare the bioactivity of SALMFamide neuropeptides from the starfish Asterias rubens using various starfish muscle preparations. In this study, the bioactivity of the L-type SALMFamide neuropeptides from the starfish A. rubens, AYHTGLPFamide (SALMFa-A) and the derivative AYHSALMFamide (SALMFa-B) was investigated. The neuropeptides were applied on Asterias amurensis apical muscle, tube feet, which revealed that the neuropeptides exhibit relaxing activity on apical muscle but no activity on tube feet. The native SALMFa-A peptide had lower relaxing activity on the apical muscle compared to the derivative peptide SALMFa-B. The relaxing activity of two neuropeptides also was compared with those on the apical muscle of Patiria pectinifera, which revealed relaxing activity as well as SALMFamide-S1 and S2 neuropeptides. Moreover, the investigation of SALMFa-A and SALMFa-B peptides' bioactivity on P. pectinifera cardiac stomach muscle also showed slight relaxing activity.

• Journal of Animal Science and Technology
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• v.51 no.6
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• pp.459-470
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• 2009

The aim of this study was to analyze the proteome of proliferating bovine satellite cells from longissimus dorsi, deep pectoral and semitendinosus muscle depots which had been subjected to hormonal deprivation or addition in culture. For hormone deprivation or addition studies, the cells were either grown in 10% charcoal-dextran stripped fetal bovine serum (CD-FBS) or in 10% FBS supplemented medium. Further to analyze the effect of insulin like growth factor (IGF-1) and testosterone (TS), the cells were grown in 10% CD-FBS containing IGF-1 (10 ng/ml) or TS (10 nM). Results have shown that hormone deprivation had a negative impact on proliferation of the cells from each of the muscle depots. In case of IGF-1 and TS addition, the proliferation levels were low compared with that of the cells grown in 10% FBS. Hence, to gain the insights of the proteins that are involved in such divergent levels of proliferation, the proteome of such satellite cells proliferating under the above mentioned conditions were analyzed using 2D-DIGE and MALDI-ToF/ToF. Thirteen proteins during hormone deprivation and nine proteins from hormone addition were found to be differentially expressed in all the cultures of the cells from the three depots. Moreover, the results highlighted in this study offer a role for each differentially expressed protein with respect to its effect on positive or negative regulation of cell proliferation.