Development of real-time reverse transcription polymerase chain reaction assays to quantify insulin-like growth factor receptor and insulin receptor expression in equine tissue.

The research article discusses the development of assays to measure insulin-like growth factor 1 receptor and insulin receptor expression in horse tissue, helping to advance knowledge in insulin and insulin-like growth factor 1 receptor physiology in equines.

Objective and Background of the Study

• The authors developed real-time reverse transcription polymerase chain reaction (RT-PCR) assays to quantify the expression of insulin-like growth factor 1 receptor (IGF1R) and insulin receptor (IR) in equine tissues.
• The research was inherently based on the critical role that insulin and insulin-like growth factor system (comprising of IGF1, IGF2, IGF1R, IGF2R and six insulin-like growth factor-binding proteins) play in muscle metabolism and key aspects of both male and female reproduction. The development, growth and maintenance of cells in mammals are also profoundly influenced by insulin and insulin-like growth factors.

Methodology and Results

• RT-PCR assays were used to quantify and analyse very small amounts of messenger ribonucleic acid (mRNA), corresponding to IGF1R and IR.
• The sensitivity of the assays were tested where results showed 192 copies/μL for IGF1R mRNA and 891 copies/μL for IR respectively, at a 95% limit of detection.
• The efficiency of the assays was also measured, with IGF1R assay efficiency at 1.01 and IR assay efficiency at 0.95.
• The assays had a broad linear range of detection (seven logs for IGF1R and six logs for IR).
• Varying concentration levels of IGF1R and IR mRNA were detected in different tissue samples. Low concentrations were observed in endometrium, lung, and spleen samples, while high concentrations were found in heart, muscle, and kidney samples. This observation is supposedly linked to the high level of glucose metabolism and utilisation in the latter tissues.

Significance and Conclusion

• The assays designed for identifying and measuring IGF1R and IR mRNA expression proved to be effective on equine tissue. This not only validates the use of such assays but advances understanding in crucial physiological processes in horses that involve insulin and IGF1R.
• The research contributes significantly to the existing knowledge regarding muscle metabolism, cell growth and differentiation, and reproductive aspects in equines. It provides a potential roadmap for future research in equine physiology and medicine.