Expression of insulin receptor substrates 1–3, glucose transporters GLUT‐1–4, signal regulatory protein 1α, phosphatidylinositol 3‐kinase and protein kinase B at the protein level in the human testis

• Published in: Anatomical science international 2005-06, Vol.80 (2), p.91-96
• Main Authors: Kokk, Kersti, Veräjänkorva, Esko, Laato, Matti, Wu, Xiao‐Ke, Tapfer, Helle, Pöllänen, Pasi
• Format: Article
• Language: English
• Subjects: 1-Phosphatidylinositol 3-kinase; AKT protein; Cytokines; Glucose transporter; glucose transporters; Growth factors; Immunohistochemistry; Insulin; Insulin receptor substrate 1; insulin receptor substrates; insulin signaling; Interstitial cells; Kinases; Macrophages; Phosphatidylinositol kinase; Phosphorylation; Proteins; Sertoli cells; Signal transduction; Spermatocytes; testis; Tyrosine; Western blotting
• ISSN: 1447-6959; 1447-073X
• DOI: 10.1111/j.1447-073x.2005.00091.x

Insulin receptor substrates (IRS) mediate the biological actions of insulin, growth factors and cytokines. This action is via receptor‐mediated tyrosine phosphorylation of IRS proteins. The aim of present study was to demonstrate the distribution of IRS‐1–3, the glucose transporter class I subfamily (GLUT‐1–4), signal regulatory protein 1α (SIRP1α), protein kinase B (PKB) and phosphatidylinositol kinase (PI3‐K) in the human testis to determine whether signal transduction mediated by these proteins is active in testicular cells. In the present study, the expression of IRS‐1–3, GLUT‐1–4, SIRP1α, PI3‐K and PKB was studied in the human testis at the protein level using immunohistochemistry and western blotting. A positive immunoreaction for IRS‐1 was found in the human testis in peritubular myoid cells and macrophage‐like interstitial cells. A positive immunoreaction for GLUT‐3 was found in the human testis in Sertoli cells, peritubular myoid cells, early spermatocytes, macrophage‐like interstitial cells and cells in the small vessels walls. Western blotting demonstrated IRS‐1, IRS‐2 and GLUT‐3 proteins in the human testis. Expression of IRS‐3, GLUT‐1, GLUT‐2, GLUT‐4, SIRP1α, PI3‐K and PKB was not detected in the human testis. The results of the present study suggest that proteins like insulin and certain cytokines using IRS‐1, IRS‐2 and GLUT‐3 in their signal transduction pathways can have effects on different cell types of the testis in humans.