Irisin

Metabolic dysfunction in skeletal muscle is a major contributor to the development of type 2 diabetes. Endurance exercise training has long been established as an effective means to directly restore skeletal muscle glucose and lipid uptake and metabolism. However, in addition to the direct effects of skeletal muscle on glucose and lipids, there is renewed interest in the ability of skeletal muscle to coordinate metabolic activity of other tissues, such as adipose tissue and liver. The purpose of this study was to examine the effects of endurance exercise on the expression level of two novel muscle-derived secreted factors, or myokines, Myonectin and Fibronectin type III domain containing 5 (FNDC5), the precursor for Irisin. Methods. We performed immunoblot analysis and quantitative real-time PCR analysis of Myonectin and FNDC5 in the diaphragm muscles of obese Zucker rat (OZR) and lean Zucker rat (LZR) with 9 weeks of aerobic training on a motorized treadmill. Results. We show that myonectin gene expression is increased in the OZR model of obesity and decreases with exercise in both lean and obese Zucker rats. Conversely, myonectin protein concentration was elevated with exercise. Similarly, FNDC5 mRNA levels are significantly higher in the OZR, however exercise training had no effect on the expression level of FNDC5 in either the LZR or OZR. We did not observe any difference in muscle protein content of Irisin with obesity or exercise. Conclusion. Our data shows that exercise training does not increase either FNDC5 or myonectin gene expression, indicating that increased transcriptional regulation of these myokines is not induced by exercise. However, our data also indicates a yet to be explored disconnect between myonectin gene expression and protein content. Further, this report highlights the importance of verifying reference genes when completing gene expression analysis. We found that many commonly used reference genes varied significantly by obesity and/or exercise and would have skewed the results of this study if used to normalize gene expression data. The unstable reference genes include: beta-Actin, beta-2-microglobulin, Non-POU domain containing, octamer-binding, Peptidylprolyl isomerase H, 18S ribosomal RNA, TATA box binding protein and Transferrin receptor.

Background and Aim: Irisin, a novel myocyte-secreted hormone, was proposed to mediate some of the beneficial effects of exercise such as browning of adipocytes, thermogenesis, and metabolic homeostasis. Recently, several animals’ models’ studies have been performed to investigate the therapeutic impact of irisin in several disorders. Several interventional trials used different doses. However, optimum dose was not determined. This systematic review aims to identify the optimal dose of interventional irisin in mice and rat animal models. Materials and Methods: Online databases PubMed, Google Scholar, and Springer were systematically searched from 2012 to 2019. The words searched were irisin, irisin and animal model, physical activity, and irisin and irisin dosage. Non-irisin doses, in vitro studies, and factors influencing irisin levels were excluded. Results: Eleven of the total 391 qualifying studies were included. A daily injection of 500 μg/kg irisin may be the optimum dose of ef...

10.30699/jambs.29.134.125 Background & Objective: Irisin is considered as a candidate to treat obesity and metabolic diseases. Therefore, the aim of this study was a systematic review and meta-analysis to define the effective modes of exercise on irisin concentration in adults. Materials & Methods: Google Scholar, PubMed, Medline, Scopus, Science Direct, and references lists of articles were searched until April 25, 2020. To study the impact of exercise duration (short-term and long-term) on the pre-test and post-test concentration of irisin, 21 studies with 384 subjects were evaluated. Results: In the present study, a significant increase was found in irisin level in longterm resistance training (LTRT) intervention groups (MD:-0.61 ng/ml, 95% CI [-1.12, 0.09], P=0.02). However, no significant changes were reported in the groups of longterm aerobic training, short-term aerobic training, and short + long term aerobic training. Conclusion: The analysis showed that only LTRT among the types of exercise can elevate irisin concentration. Therefore, LTRT seems to have more beneficial influences, compared to other modes of exercise in inclusive irisin responses.

This is the first study to determine the effects of strenght exercises on irisin and correlation of bady composition and irisin. The purpose of this study was to determine the effects on body composition and irisin of static strength exercises with Tera-Bant® in elite boxers. 9 volunteered elite male boxers participate in the study who are non-smokers and did not use any nutritional supplements. Boxers were instructed to perform strength exercises with Thera-Band for 3 days a week for 8 weeks. Blood samples were taken before exercises (resting), after the first exercise (acute) and after 8 weeks following the last exercise (chronic), and measurement of body fats were made at the same time. Irisin levels of blood were examined. Statistical analyses were carried out using the SPSS 22 for Windows. The data were found to not be distributed normally. Thus, Friedman, Wilcoxon, Mann-Whitney U and Speraman's correlations tests were used. The results were evaluated using an alpha level of .05. Body Fat Percentage (BFP) and Fat Mass (FM) levels of athletes increased, Lean Mass (LM) decreased relatively both after a single session and after 8 weeks. While irisin concentration increased after a single session, (correlation in pre exercise and after a single exercise. Static strength exercise is effective on body fat both acutely and chronically, and effective on irisin only acute. Farther, the body fat and irisin are related to the negative.