Dataset Information

Testosterone supplementation improves insulin responsiveness in HFD fed male T2DM mice and potentiates insulin signaling in the skeletal muscle and C2C12 myocyte cell line.

ABSTRACT:

Background

Type 2 Diabetes Mellitus (T2DM) is characterised by hyperglycemia due to the incidence of insulin resistance. Testosterone supplementation has been shown to have a positive co-relation with improved glycemic control in T2DM males. Clinical studies have reported that Androgen Replacement Therapy (ART) to hypogonadic males with T2DM resulted in improved glycemic control and metabolic parameters, but, these studies did not address in detail how testosterone acted on the key glucose homeostatic organs.

Method

In this study, we delineate the effect of testosterone supplementation to high-fat diet (HFD) induced T2DM in male C57BL6J mice and the effect of testosterone supplementation on the skeletal muscle insulin responsiveness. We also studied the effect of testosterone on the insulin signaling pathway proteins in C2C12 myocyte cells to validate the in vivo findings.

Results

We found that testosterone had a potentiating effect on the skeletal muscle insulin signaling pathway to improve glycaemic control. We demonstrate that, in males, testosterone improves skeletal muscle insulin responsiveness by potentiating the PI3K-AKT pathway. The testosterone treated animals showed significant increase in the skeletal muscle Insulin Receptor (IR), p85 subunit of PI3K, P-GSK3? (Ser-21), and P-AKT (Ser-473) levels as compared to the control animals; but there was no significant change in total AKT and GSK3?. Testosterone supplementation inhibited GSK3? in the myocytes in a PI3K/AKT pathway dependent manner; on the other hand GSK3? gene expression was reduced in the skeletal muscle upon testosterone supplementation.

Conclusion

Testosterone increases insulin responsiveness by potentiating insulin signaling in the skeletal muscle cells, which is in contrast to the increased insulin resistance in the liver of testosterone treated T2DM male animals.

SUBMITTER: Pal M

PROVIDER: S-EPMC6834245 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Publications

Testosterone supplementation improves insulin responsiveness in HFD fed male T2DM mice and potentiates insulin signaling in the skeletal muscle and C2C12 myocyte cell line.

Pal Madhuraka M Khan Jasim J Kumar Ravi R Surolia Avadhesha A Gupta Sarika S

PloS one 20191106 11

<h4>Background</h4>Type 2 Diabetes Mellitus (T2DM) is characterised by hyperglycemia due to the incidence of insulin resistance. Testosterone supplementation has been shown to have a positive co-relation with improved glycemic control in T2DM males. Clinical studies have reported that Androgen Replacement Therapy (ART) to hypogonadic males with T2DM resulted in improved glycemic control and metabolic parameters, but, these studies did not address in detail how testosterone acted on the key gluco ...[more]

PMID: 31693697

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Project description:Background Tianhuang formula (THF) is a Chinese medicine prescription that is patented and clinically approved, and has been shown to improve energy metabolism, but the underlying mechanism remains poorly understood. The purpose of this study is to clarify the potential mechanisms of THF in the treatment of type 2 diabetes mellitus (T2DM). Methods A murine model of T2DM was induced by high-fat diet (HFD) feeding combined with low-dose streptozocin (STZ) injections, and the diabetic mice were treated with THF by gavaging for consecutive 10 weeks. Fasting blood glucose (FBG), serum insulin, blood lipid, mitochondrial Ca2+ (mCa2+) levels and mitochondrial membrane potential (MMP), as well as ATP production were analyzed. The target genes and proteins expression of visceral adipose tissue (Vat) was tested by RT-PCR and western blot, respectively. The underlying mechanism of the regulating energy metabolism effect of THF was further explored in the insulin resistance model of 3T3-L1 adipocytes cultured with dexamethasone (DXM). Results THF restored impaired glucose tolerance and insulin resistance in diabetic mice. Serum levels of lipids were significantly decreased, as well as fasting blood glucose and insulin in THF-treated mice. THF regulated mCa2+ uptake, increased MMP and ATP content in VAT. THF increased the mRNA and protein expression of AMPK, phosphorylated AMPK (p-AMPK), MICU1, sirtuin1 (SIRT1) and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α). THF could increase the mCa2+ level of 3T3-L1 adipocytes and regulate mitochondrial function. The protein expression of AMPK, p-AMPK, mCa2+ uniporter (MCU) and MICU1 decreased upon adding AMPK inhibitor compound C to 3T3-L1 adipocytes and the protein expression of MCU and MICU1 decreased upon adding the MCU inhibitor ruthenium red. Conclusions These results demonstrated that THF ameliorated glucose and lipid metabolism disorders in T2DM mice through the improvement of AMPK/MICU1 pathway-dependent mitochondrial function in adipose tissue. Supplementary Information The online version contains supplementary material available at 10.1186/s12906-023-04009-5. Highlights • AMPK-MCU/MICU1 mediated mCa2+ uptake in adipose tissue played an important role in insulin resistance • THF restored impaired glucose tolerance and insulin resistance in diabetic mice induced by HFD/STZ • THF improved the mitochondrial function of in T2DM mice via AMPK-MICU1 pathway Supplementary Information The online version contains supplementary material available at 10.1186/s12906-023-04009-5.

Project description:Testosterone induces cardiac hypertrophy through a mechanism that involves a concerted crosstalk between cytosolic and nuclear signaling pathways. Nuclear factor of activated T-cells (NFAT) is associated with the promotion of cardiac hypertrophy, glycogen synthase kinase-3β (GSK-3β) is considered to function as a negative regulator, mainly by modulating NFAT activity. However, the role played by calcineurin-NFAT and GSK-3β signaling in testosterone-induced cardiac hypertrophy has remained unknown. Here, we determined that testosterone stimulates cardiac myocyte hypertrophy through NFAT activation and GSK-3β inhibition. Testosterone increased the activity of NFAT-luciferase (NFAT-Luc) in a time- and dose-dependent manner, with the activity peaking after 24 h of stimulation with 100 nM testosterone. NFAT-Luc activity induced by testosterone was blocked by the calcineurin inhibitors FK506 and cyclosporine A and by 11R-VIVIT, a specific peptide inhibitor of NFAT. Conversely, testosterone inhibited GSK-3β activity as determined by increased GSK-3β phosphorylation at Ser9 and β-catenin protein accumulation, and also by reduction in β-catenin phosphorylation at residues Ser33, Ser37, and Thr41. GSK-3β inhibition with 1-azakenpaullone or a GSK-3β-targeting siRNA increased NFAT-Luc activity, whereas overexpression of a constitutively active GSK-3β mutant (GSK-3βS9A) inhibited NFAT-Luc activation mediated by testosterone. Testosterone-induced cardiac myocyte hypertrophy was established by increased cardiac myocyte size and [3H]-leucine incorporation (as a measurement of cellular protein synthesis). Calcineurin-NFAT inhibition abolished and GSK-3β inhibition promoted the hypertrophy stimulated by testosterone. GSK-3β activation by GSK-3βS9A blocked the increase of hypertrophic markers induced by testosterone. Moreover, inhibition of intracellular androgen receptor prevented testosterone-induced NFAT-Luc activation. Collectively, these results suggest that cardiac myocyte hypertrophy induced by testosterone involves a cooperative mechanism that links androgen signaling with the recruitment of NFAT through calcineurin activation and GSK-3β inhibition.

Dataset Information

Testosterone supplementation improves insulin responsiveness in HFD fed male T2DM mice and potentiates insulin signaling in the skeletal muscle and C2C12 myocyte cell line.

Background

Method

Results

Conclusion

Publications

Testosterone supplementation improves insulin responsiveness in HFD fed male T2DM mice and potentiates insulin signaling in the skeletal muscle and C2C12 myocyte cell line.

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