Steroid hormones progesterone (P4) and 17β-estradiol (E2) not only have important functions in regulation of reproductive processes in mammals but also have direct effects on spermatozoa. There can be induction of the acrosome reaction in ram spermatozoa by P4 and E2 and, in the present study, there was further investigation of mechanisms underlying this effect. In a medium containing agents that increase cAMP, the presence of both P4 and E2 led to changes in the localization of proteins phosphorylated in tyrosine residues evaluated by indirect immunofluorescence. The inclusion of P4 at 1 μM in the media induced an increase in Ca²⁺_i and mobilization in the area of the acrosome (Fluo-4 and Rhod-5 staining, respectively), an increase in ROS (H₂DCFDA staining) and a substantial disruption of the acrosome (evaluated using RCA), while E2 did not have these effects. There were no effects on cAMP concentrations or PKA activity with inclusion of these hormones in the media. The inclusion of P4 at 100 pM in the media led to changes in values for sperm kinematic variables which could indicate there was an inhibition of the hyperactivation caused by agents that induce an increase in cAMP concentrations. In conclusion, results from the present study indicate that P4 and E2 promote mechanisms regulating the acrosome reaction in ram spermatozoa, however, these effects on mechanisms are different for the two hormones, and for E2, require further clarification.

类固醇激素黄体酮 (P4) 和 17β-雌二醇 (E2) 不仅在调节哺乳动物生殖过程中具有重要作用，而且对精子也有直接影响。P4 和 E2 可以诱导公羊精子的顶体反应，在本研究中，进一步研究了这种作用的潜在机制。在含有增加 cAMP 的试剂的培养基中，P4 和 E2 的存在导致通过间接免疫荧光评估的酪氨酸残基磷酸化蛋白质的定位发生变化。在培养基中包含 1 μM 的 P4 诱导 Ca ²⁺ _i的增加和顶体区域的动员（分别为 Fluo-4 和 Rhod-5 染色），ROS 的增加（H ₂DCFDA 染色）和顶体的实质性破坏（使用 RCA 评估），而 E2 没有这些影响。在培养基中加入这些激素对 cAMP 浓度或 PKA 活性没有影响。在培养基中包含 100 pM 的 P4 导致精子运动变量值的变化，这可能表明存在对诱导 cAMP 浓度增加的试剂引起的过度活化的抑制。总之，本研究的结果表明 P4 和 E2 促进了调节公羊精子顶体反应的机制，但是，这两种激素对机制的影响不同，而 E2 需要进一步澄清。