Green C M, Cockle S M, Watson P F, Fraser L R
Biomedical Sciences Division, King's College London, Strand, United Kingdom.
Mol Reprod Dev. 1994 Jun;38(2):215-21. doi: 10.1002/mrd.1080380213.
Pyroglutamylglutamylprolineamide, a prostatic tripeptide with structural similarities to thyrotrophin-releasing hormone (TRH), has been found in the seminal plasma of several mammalian species, suggestive of a biological function relating to spermatozoa. Using chlortetracycline (CTC) fluorescence analysis and in vitro fertilization, we have obtained evidence that the tripeptide stimulates mouse sperm capacitation and fertilizing ability in vitro. The tripeptide at concentrations from 5-500 nM was added to sperm suspensions and cells were assessed with CTC after 40 min, insufficient time for complete capacitation by a majority of spermatozoa under standard conditions of incubation. Concentrations of 25 nM and higher significantly promoted capacitation, as evidenced by a decrease in the proportion of acrosome-intact F pattern spermatozoa, characteristic of uncapacitated cells, and an increase in the proportion of acrosome-intact B pattern spermatozoa, characteristic of uncapacitated cells. However, there was no significant stimulation of acrosomal exocytosis. These results suggested that peptide-treated cells would be more fertile than their untreated counterparts. This was confirmed using in vitro fertilization, where the presence of 100 nM peptide during sperm preincubation and gamete coincubation significantly stimulated fertilizing ability (peptide, 56.5% of oocytes fertilized; controls, 26.5%). Comparison of the prostatic tripeptide and TRH effects on capacitation revealed that TRH at a concentration of 250 nM was as effective as the prostatic tripeptide in promoting the F-->B transition but was less effective or ineffective at lower concentrations. In vitro fertilization assessment of the two peptides, at 100 nM, revealed that only the prostatic tripeptide significantly stimulated fertility. Again, this was consistent with the CTC analyses.(ABSTRACT TRUNCATED AT 250 WORDS)
焦谷氨酰谷氨酰脯氨酰胺是一种前列腺三肽，其结构与促甲状腺激素释放激素（TRH）相似，已在几种哺乳动物的精浆中被发现，这表明它具有与精子相关的生物学功能。利用金霉素（CTC）荧光分析和体外受精技术，我们获得了证据，证明该三肽能在体外刺激小鼠精子获能和受精能力。将浓度为5 - 500 nM的三肽添加到精子悬液中，40分钟后用CTC评估细胞，在标准孵育条件下，这段时间不足以使大多数精子完全获能。25 nM及更高浓度显著促进了获能，表现为未获能细胞特有的顶体完整F型精子比例下降，以及未获能细胞特有的顶体完整B型精子比例增加。然而，对顶体胞吐作用没有显著刺激。这些结果表明，经肽处理的细胞比未处理的细胞更具生育能力。这一点通过体外受精得到了证实，在精子预孵育和配子共孵育过程中存在100 nM肽时，显著刺激了受精能力（肽处理组，56.5%的卵母细胞受精；对照组，26.5%）。比较前列腺三肽和TRH对获能的影响发现，浓度为250 nM的TRH在促进F型向B型转变方面与前列腺三肽一样有效，但在较低浓度下效果较差或无效。对两种肽在100 nM时进行的体外受精评估显示，只有前列腺三肽显著刺激了生育能力。同样，这与CTC分析结果一致。（摘要截短至250字）
