Regulation of androgen receptor mRNA and protein in the rat testis by testosterone
Adult rats were treated with ethane dimethane sulphonate (EDS), an agent that destroys Leydig cells. Within 5 days after EDS treatment, the levels of testosterone (T) in the circulation and in the testis were decreased to very low values, which makes it possible to manipulate the testicular T concentration through administration of exogenous T. Spermatogenesis was not markedly affected within 5 days after EDS treatment, also not in the absence of T administration.
In testes of EDS-treated rats, the androgen receptor mRNA (ARmRNA) level remained unaltered for 5 days. In ventral prostate, however, this treatment caused a pronounced upregulation of the level of ARmRNA, which could be counteracted by implantation of silastic T implants immediately after EDS treatment.
In EDS-treated rats carrying a T implant and in untreated rats, the same number of specific [3H]R1881 binding sites was observed using a total testis nuclear fraction (Scatchard analysis). In testes from EDS-treated rats without T implants, androgen receptors (AR) did not fractionate into the nuclear fraction; however, the total testicular AR content in these animals (measured by nuclear [3H]R1881 binding after receptor transformation through injection of a high dose of T, 2 h before killing the rats) remained unaltered.
Immunoprecipitation and Western blotting using anti N-terminal antibodies seemed to indicate that the total testicular amount of AR protein in the EDS-treated rats was very low as compared to that in EDS-treated rats carrying T implants and in untreated rats. Even after receptor retransformation (by injection of a high dose of T) the receptors were not quantitatively detected by immunoprecipitation and Western blotting. This may point to a structural modification of the AR that occurs in the prolonged absence of androgens.
|Persistent URL||dx.doi.org/10.1016/0960-0760(91)90200-O, hdl.handle.net/1765/55125|
|Journal||The Journal of Steroid Biochemistry and Molecular Biology|
Blok, L.J, Bartlett, J.M.S, Bolt-de Vries, J, Themmen, A.P.N, Brinkmann, A.O, Weinbauer, G.F, … Grootegoed, J.A. (1991). Regulation of androgen receptor mRNA and protein in the rat testis by testosterone. The Journal of Steroid Biochemistry and Molecular Biology, 40(1-3), 343–347. doi:10.1016/0960-0760(91)90200-O