# Role of Irisin in Endocrine and Metabolic Disorders--Possible New Therapeutic Agent?
## 12 Conclusions  
Since the discovery of irisin, much attention has been drawn to its potential therapeutic implications in the treatment of a variety of endocrine and metabolic diseases.  
\begin{table}
\begin{tabular}{c c c c} \hline
**Therapeutical Agent** & **Study Type** & **Action** & **References** \\ \hline INSULIN & humans with T2 DM & \(\uparrow\) serum irisin & [PERSON] et al., 2016 [51] \\ \hline \multirow{4}{*}{LEPTIN} & \multirow{4}{*}{obese mice} & Up-regulation of FNDC5 in skeletal muscle \(\rightarrow\)\(\uparrow\) irisin & \multirow{4}{*}{[PERSON] et al., 2015 [52]} \\  & & \(\downarrow\) irisin expression in subcutaneous fat & \\ \hline METFORMIN & diabetic obese mice & Up-regulation of FNDC5 in skeletal muscle \(\rightarrow\)\(\uparrow\) irisin & \multirow{4}{*}{[PERSON] et al., 2015 [53]} \\ \cline{1-1} \cline{3-3}  & & Up-regulation of FNDC5 in skeletal muscle \(\rightarrow\)\(\uparrow\) irisin & \\ \cline{1-1} \cline{3-3}  & & & \\ \cline{1-1} \cline{3-3}  & & & \\ \cline{1-1} \cline{3-3}  & & & \\ \cline{1-1} \cline{3-3}  & & & \\ \hline FENOFIBRATE & male C57 BL/6 mice & irisin induction & [PERSON] et al., 2015 [55] \\ \hline FEMOFIBRATE & humans with T2 DM & \(\downarrow\) irisin in serum & \multirow{2}{*}{[PERSON] et al., 2015 [56]} \\ \cline{1-1} \cline{3-3} SIMVASTATIN & \multirow{2}{*}{\
\begin{tabular}{c} humans with \\ hypercholesterolemiaemia \\ \end{tabular} } & \(\uparrow\) irisin & \multirow{2}{*}{[PERSON] et al., 2013 [57]} \\ \cline{1-1} \cline{3-3} EXENATIDE & humans with T2 DM & \(\uparrow\) irisin & \multirow{2}{*}{[PERSON] et al., 2016 [58]} \\ \cline{1-1} \cline{3-3} DIHYDROMYRICETIN & \multirow{2}{*}{
\begin{tabular}{c} humans \\ rats \\ \end{tabular} } & \(\uparrow\) irisin & \multirow{2}{*}{[PERSON] et al., 2015 [59]} \\ \cline{1-1} \cline{3-3} MELATONIN & Diabetic fatty rats & \(\uparrow\) irisin & \multirow{2}{*}{[PERSON]. [PERSON] et al., 2013 [60]} \\ \hline \end{tabular}
\end{table}
Table 2: The effects of pharmacological agents on irisin.  
Taking into account that both irisin and thyroid hormones are associated with metabolism, muscle physiology, and body energy expenditure, as well as the fact that serum irisin concentrations vary, depending on TSH and fT4 in thyroid dysfunction, it can be postulated that irisin and thyroid function are interconnected. The role of irisin in thyroid disorders needs additional research, in terms of animal-based studies, in order to clarify its therapeutic potential in thyroid dysfunctions.  
Proving the potential roles of irisin in regulating hepatic and pancreatic islet functions would provide evidence supporting irisin as a mediator for protection against obesity, diabetes, and metabolic syndrome. This will pave the way for irisin to be used as a preventative and therapeutic agent, as well as for PCOS, SGA and hypothalamic syndromic obesity.  
The influence of irisin on bone health is still under debate. Clinical (inverse correlation between the number of vertebral menopausal osteoporortic fracture and irisin) and experimental (infusion of r-irisin in mice caused a reduction in osteoclasts and exerted an anabolic effect on the bone) data have suggested that irisin may be an important target for the therapy of decreased bone density. Further studies are necessary, in order to prove irisin's therapeutic potential in osteoporosis.  
While it may seem \"too good to be true\", irisin offers ample opportunities for future research, in order to determine its optimal roles in the treatment of endocrine and metabolic disorders.  
Conceptualization L.L. and C.P.; methodology, M.-C.U.; software, L.T.; validation, L.L., C.P. and M.-C.U.; formal analysis, L.M. and L.A.; investigation, C.P.; resources, L.T.; data curation, L.L.; writing--original draft preparation, L.L.; writing--review and editing, C.P.; visualization, M.-C.U.; supervision, L.M. and L.A. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The authors declare no conflict of interest.