Fig. 6. Studies by co-immunoprecipitation to investigate the association of the protease inhibitor ₂-MG with TGF-ß3, cathepsin L, and TJ-associated, AJ-associated and cytoskeletal proteins during CdCl₂-induced BTB damage. Immunoprecipitation was performed using either anti-₂-MG or anti-TGF-ß3 antibody and lysates of testes from rats that had received CdCl₂ (3 mg/kg b.w., i.p.) at 0, 24 and 96 hours earlier. For positive controls, lysates of testes from rats (150 µg protein per lane) at 20 hours after CdCl₂ treatment without immunoprecipitation were used since at this time most target proteins pertinent to our studies were induced (see Fig. 2), confirming the specificity of the antibodies. Only a set of representative data is shown, but two other experiments using different rat testis lysates yielded identical results.