[The effect of noradrenaline, adrenaline and acetylcholine on contractility of the uterus of the guinea pig after testosterone administration].

: The reactivity of the isolated guinea pig uterus was studied after single (0.5 h before experiment) and repeated (7 days) in vivo testosterone administration in the dose of 10 mg.kg-1. In vitro testosterone was applied in the dose of 5.8 x 10(-5) mol. The reactivity of the isolated guinea pig uterus to norepinephrine, epinephrine, and acetylcholine was evaluated. These substances were applied cumulatively in doses of 10(-8) - 10(-4) mol.I-1. The changes of isometric contractions of the uterus were evaluated by the magnitude of the maximal response and by the pD2 value. The contractile response of the guinea pig uterus to all the mediators studied was decreased both after in vitro and in vivo administration of testosterone. The most pronounced change in the pD2 value was induced by single testosterone administration. The results suggest that, similarly as female sex hormones, testosterone may influence uterine function by its effect at receptor and nonreceptor level.