Variations in soluble and particulate ABP of rat testis during sexual development.
Androgen binding activity (ABP) was determined in two different fractions of developing rat testicular homogenates: in cytosol (cABP) and in a particulate fraction isolated by differential centrifugation (pABP). Homogenates were prepared under stabilization conditions by adding 350 nM testosterone to the homogenization buffer. cABP and pABP concentrations were maximal in 22- to 32-day-old animals, to decrease thereafter during sexual maturation. However, both cABP and pABP increased with age when results were expressed on a per organ basis. pABP could be solubilized under conditions in which it could retain its binding activity. It was then photoaffinity labeled and chromatographed on a Sephadex G 200 column using cytosolic epididymal ABP as a control. Similarities between cABP and pABP include not only the same androgen binding characteristics but also the same exclusion volume after Sephadex G 200 chromatography. Since pABP is only present in Sertoli cells, it might represent ABP before being secreted. Because of its intracellular localization, it could play a role in the compartmentalization of androgens within the testis.
D000727:Androgen-Binding Protein / Q000302:isolation & purification*; D000818:Animals; D002850:Chromatography, Gel; D003600:Cytosol / Q000032:analysis; D004822:Epididymis / Q000032:analysis; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012741:Sexual Maturation; D013737:Testis / Q000032:analysis*
D000727:Androgen-Binding Protein