Data from: Toxoplasma gondii infection enhances testicular steriodogeneis in rat

The protozoan parasite Toxoplasma gondii enhances the sexual attractiveness of infected male rats and attenuates the innate fear of cat odor in infected individuals. These behavioral changes plausibly lead to greater transmission of parasites through sexual and trophic routes, respectively. Testosterone, a testicular steroid, is known to reduce fear and enhance sexual attractiveness in males. Here, we show that Toxoplasma gondii infection enhances expression of genes involved in facilitating synthesis of testosterone, resulting in greater testicular testosterone production in male rats. In several species, testosterone mediates trade-offs between sexually selected traits and life-history decisions. Augmentation of testosterone synthesis by Toxoplasma gondii suggests that parasites may manipulate these trade-offs in rats.

原生动物寄生虫刚地弓形虫（Toxoplasma gondii）可增强受感染雄性大鼠的性吸引力，并减弱受感染个体对猫气味的先天恐惧。这些行为变化可分别通过性传播与营养级传播途径，合理提升寄生虫的传播效率。睾酮（testosterone）作为一种睾丸类固醇激素，已知可降低雄性个体的恐惧反应并增强其性吸引力。本研究发现，刚地弓形虫感染可上调参与睾酮合成调控的基因表达，进而提升雄性大鼠的睾丸睾酮合成水平。在多个物种中，睾酮介导了性选择性状与生活史策略之间的权衡关系。刚地弓形虫对睾酮合成的增强作用表明，该寄生虫或可在大鼠体内调控这类权衡机制。