Fig. 7. Effect of diflouromethylornithine (DFMO) on contractile force in steroid-treated ventricle strips from both male (A) and female (B) rainbow trout. Strips were treated with DFMO (10 mmol l^–1) for 10 min prior to exposure to 11-ketotestosterone (11KT; 0.3 µmol l^–1), testosterone (T; 0.3 µmol l^–1), cortisol (C; 0.1 µmol l^–1 in males and 0.01 µmol l^–1 in females) or estradiol (E2; 1.0 nmol l^–1). DFMO had no independent effect on contractile force; however, DFMO did block the inotropic effects of androgens, C and E2. All values are means + S.E.M. (N=6–9). *P<0.05 versus EtOH control strips.