Effect of Exogenous Testosterone and Finasteride on Morphine-Induced Analgesia in Male Syrian Mice Using the Formalin Test

This study examined the impact of exogenous testosterone and finasteride on morphine-induced analgesia in 42 male Syrian mice. It found that exogenous testosterone reduced morphine's pain-relieving effects, suggesting testosterone interfered with morphine's efficacy. In contrast, finasteride enhanced morphine's analgesic effect by likely blocking the influence of endogenous testosterone, which otherwise diminished morphine's effectiveness. The results suggested that testosterone and its metabolites might increase pain sensitivity, while finasteride could enhance morphine's pain relief by counteracting testosterone's effects.