The steroid hormones 17-β estradiol (E2) and progesterone (P4) can regulate capacitation, hyperactive motility, and the acrosome reaction (AR) during the sperm transit through the female tract. Moreover, exogenous P4 and E2 can induce the AR in ovine spermatozoa, and progesterone receptor (PR) and estrogen receptors (ERα and ERβ) are present in these cells. Thus, to investigate whether the effects both steroid hormones in ram sperm capacitation and AR are receptor-mediated, we incubated them with receptor agonists (tanaproget 1 μM and 5 μM for PR or resveratrol 5 μM and 10 μM for ER) or antagonists (mifepristone 4 μM and 40 μM for PR or tamoxifen 5 μM and 10 μM for ER) in capacitating conditions. The addition of receptor modulators did not affect sperm viability or total motility, although changes in progressive motility were detected. The incubation with both receptor agonists increased the percentage of acrosome-reacted spermatozoa, evaluated by chlortetracycline staining, when compared with the capacitated nontreated sample (Cap-C, P < 0.001). Moreover, the ER agonist resveratrol 10 μM provoked a greater AR than E2 (P < 0.01). Furthermore, the incubation with the receptor antagonists prevented the induction of the AR by P4 or E2, as the antagonists-treated spermatozoa presented a similar CTC pattern to that of Cap-C. In conclusion, these results confirm that P4 and E2 can induce the AR in ram spermatozoa and that this effect is receptor-mediated.

类固醇激素 17-β 雌二醇 (E2) 和孕酮 (P4) 可以调节精子通过女性生殖道期间的获能、运动过度和顶体反应 (AR)。此外，外源性P4和E2可诱导绵羊精子发生AR，这些细胞中存在孕激素受体（PR）和雌激素受体（ERα和ERβ）。因此，为了研究类固醇激素对公羊精子获能和 AR 的影响是否都是受体介导的，我们将它们与受体激动剂（tanaproget 1 μM 和 5 μM 用于 PR 或白藜芦醇 5 μM 和 10 μM 用于 ER）或拮抗剂（米非司酮）一起孵育4 μM 和 40 μM 用于 PR 或他莫昔芬 5 μM 和 10 μM 用于 ER）在容量条件下。尽管检测到渐进性运动的变化，但受体调节剂的添加不影响精子活力或总运动性。P < 0.001)。此外，ER 激动剂白藜芦醇 10 μM 比 E2 引起更大的 AR ( P < 0.01)。此外，与受体拮抗剂的孵育阻止了 P4 或 E2 诱导 AR，因为拮抗剂处理的精子呈现出与 Cap-C 相似的 CTC 模式。总之，这些结果证实 P4 和 E2 可以在公羊精子中诱导 AR，并且这种作用是受体介导的。