Effect of gonadectomy and sex steroid replacement on TH protein and mRNA in adolescent male rats. (A) Representative immunoblots of a subset of substantia nigra samples from all five groups showing TH protein (60 kDa) and β-actin protein (43 kDa). (B) TH protein was increased by testosterone (n=10) compared to Intact (n=10) and Gdx (n=10) groups, whereas DHT (n=8) and E (n=10) did not increase TH protein. Gdx+T was significantly different to Gdx+DHT and Gdx+E, ***=p < 0.001, and significantly different to Gdx and Intact, p < 0.05 and p < 0.01, respectively. (C) TH mRNA was measured using real time qPCR. Midbrain TH mRNA relative expression was not significantly different according to treatment group.