Characterization of the insulin-like growth factors (IGF) axis in a cultured XXXX Leydig cell line (TM-3).

@entity19 @entity54850 @entity10247 @entity7424 @entity10250
Characterization of the insulin-like growth factor (IGF) axis in a cultured @entity19 Leydig cell line (TM-3) was performed. Radioimmunoassayable @entity7424 and @entity10247 concentrations in TM-3 conditioned media (CM) were below the assay detection levels. Affinity cross-linking of @entity7424 and @entity10247 to crude membranes prepared from TM-3 cells revealed both type 1 and type 2 receptors and a 31 kDa IGF binding protein (IGFBP). Immunoprecipitation of solubilized crude membranes indicated that the 31 kDa protein was membrane associated @entity10250 . Western ligand blots of CM from TM-3 cells demonstrated the presence of 24 and 28 kDa bands as major IGFBPs, and 25, 40, and 44 kDa as minor ones. The 28 kDa band could be invisible after Endoglycosidase-F treatment, suggesting that the 28 kDa IGFBP was a glycosylated form of IGFBP. The 24 kDa and 28 kDa bands were immunoprecipitated with an antibody to @entity10250 . Treatment of TM-3 cells with @entity7424 increased the levels of the 24 kDa @entity10250 , as well as 25, 28, 40, and 44 kDa IGFBPs. @entity7424 treatment also resulted in the appearance of a 29 kDa IGFBP. Neither the 25 nor 29 kDa bands were deglycosylated with Endoglycosidase-F nor immunoprecipitated by antibodies to @entity54850 . On the other hand, @entity10247 treatment resulted in a significant decrease in the 24 kDa @entity10250 .(ABSTRACT TRUNCATED AT 250 WORDS)
