Shimizu Y, Yorimitsu A, Maruyama Y, Kubota T, Aso T, Bronson R A
Department of Obstetrics and Gynecology, Faculty of Medicine, Tokyo Medical and Dental University, Japan.
Mol Hum Reprod. 1998 Jun;4(6):555-61. doi: 10.1093/molehr/4.6.555.
Progesterone, prostaglandin and follicular fluid are reported to enhance the acrosome reaction through the influx of extracellular calcium into the cytoplasm of human spermatozoa. Prostaglandins are present within the male reproductive tract, and high concentrations of prostaglandins exist in seminal fluid. In order to investigate the mechanisms by which prostaglandins enhance the acrosome reaction through calcium influx, the intracellular calcium response induced by progesterone, prostaglandin E1 (PGE1), prostaglandin E2 (PGE2) and follicular fluid was measured using fura-2. PGE1 and PGE2 promoted calcium influx dose dependently through dihydropyridine insensitive calcium channels. Refractoriness of the elevation of intracellular Ca2+ concentration ([Ca2+]i) to a second stimulus occurred when 60 microg/ml PGE1 was administered 100 s after the prior administration of 60 microg/ml of PGE1, and similarly when 1 microg/ml of progesterone was administered 100 s after the prior administration of 1 microg/ml of progesterone. Refractoriness also occurred when 60 microg/ml PGE1 was administered after the prior addition of 60 microg/ml PGE2, but did not occur between PGE1 and progesterone. Pertussis toxin (PTX) did not modify the changes in [Ca2+]i after the addition of PGE1 or PGE2. In conclusion, PGE1 and PGE2 promoted calcium influx through PTX-insensitive calcium channels which appeared to be recognized by a common receptor different from that of progesterone.
据报道，孕酮、前列腺素和卵泡液可通过细胞外钙流入人类精子细胞质来增强顶体反应。前列腺素存在于男性生殖道内，精液中存在高浓度的前列腺素。为了研究前列腺素通过钙内流增强顶体反应的机制，使用fura-2测量了孕酮、前列腺素E1（PGE1）、前列腺素E2（PGE2）和卵泡液诱导的细胞内钙反应。PGE1和PGE2通过对二氢吡啶不敏感的钙通道剂量依赖性地促进钙内流。当在先前给予60μg/ml PGE1 100秒后给予60μg/ml PGE1时，以及类似地当在先前给予1μg/ml孕酮100秒后给予1μg/ml孕酮时，细胞内Ca2+浓度（[Ca2+]i）升高对第二次刺激出现不应性。当在先前添加60μg/ml PGE2后给予60μg/ml PGE1时也出现不应性，但在PGE1和孕酮之间未出现不应性。百日咳毒素（PTX）在添加PGE1或PGE2后未改变[Ca2+]i的变化。总之，PGE1和PGE2通过对PTX不敏感的钙通道促进钙内流，这些钙通道似乎由与孕酮不同的共同受体识别。
