Resumen

CASANOVA, Marta B.. Expression of caveolin-1 in rat Leydig cells. Biocell [online]. 2006, vol.30, n.3, pp.431-438. ISSN 0327-9545.

Caveolin-1, the first member of caveolin family reported, is recognized as the structural component of caveola, a plasma membrane invagination or vesicles that are a subcompartment distinct from clathrin-coated pits. This protein is also known to be involved in cholesterol trafficking. The aim of this study was to determine the expression of caveolin-1 in adult rat Leydig cells. Testis sections incubated with an antibody to caveolin-1 showed, by immunohistochemistry, a moderate number of Leydig cells with different degrees of immunoreaction and a strong reaction in endothelial cells and in the lamina propia of seminiferous tubules. Caveolin-1 was detected in the cell cytoplasm with a granular pattern and on the cell surface of Leydig cells cultured 24 h on uncoated, laminin-1 or type IV collagen coated coverslips. We also observed a milder reaction in 3 h cultures. Immunoreaction was also detected in Leydig cells with an antibody to tyrosine-phosphorylated caveolin-1. By double immunofluorescent technique, we observed co-localization of caveolin-1 and 3β-hydroxysteroid dehydrogenase. Western blot analysis revealed a band of about 22 kDa molecular weight that was recognized with both caveolin-1 and tyrosinephosphocaveolin- 1 antibodies. Caveolin-1 is one of a few proteins with a demonstrated ability to bind cholesterol in vivo. In this context, the presence of caveolin-1 in Leydig cells may be related to cholesterol traffic -a rate limiting step in steroid biosynthesis.

Palabras clave : Testis; Leydig cells; Caveolin-1.

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