Müller K, Müller P, Herrmann A
Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, Institut für Biologie/Biophysik, Berlin.
J Reprod Fertil. 1997 Sep;111(1):81-9. doi: 10.1530/jrf.0.1110081.
The transbilayer movement and distribution of spin-labelled phospholipid analogues were studied in the plasma membrane of ram sperm cells isolated from functionally different regions of the epididymis (caput, cauda) and from the ejaculate. As already shown for ejaculated cells, (i) a rapid movement of aminophospholipid analogues phosphatidylserine and phosphatidylethanolamine from the exoplasmic to the cytoplasmic leaflet, and (ii) a slow transbilayer movement of phosphatidylcholine were observed in the plasma membrane of maturating ram sperm cells. This suggests an asymmetric steady state transbilayer distribution of phospholipids, with a preferential enrichment of aminophospholipids on the cytoplasmic leaflet of those cells. The fast inward redistribution of the aminophospholipid analogues is consistent with the presence of an aminophospholipid translocase activity in all three sperm cell preparations. The translocase activity was enhanced slightly during the epididymal transit of spermatozoa. However, compared with epididymal sperm cells, a marked increase in the aminophospholipid translocase activity and a more pronounced phospholipid asymmetry for phosphatidylethanolamine was established for ejaculated spermatozoa. The physiological relevance of the rapid removal of aminophospholipids from the exoplasmic leaflet of the plasma membrane of ram sperm cells is discussed. The quality of sperm cell fractions was characterized by the cell morphology, membrane integrity and the cellular ATP concentration.
研究了自旋标记磷脂类似物在从附睾功能不同区域（头部、尾部）及射精精液中分离出的公羊精子细胞质膜中的跨膜运动和分布情况。正如已在射出精子细胞中所显示的那样，在成熟公羊精子细胞质膜中观察到：（i）氨基磷脂类似物磷脂酰丝氨酸和磷脂酰乙醇胺从细胞外小叶快速转移至细胞质小叶；（ii）磷脂酰胆碱的跨膜运动缓慢。这表明磷脂存在不对称稳态跨膜分布，在这些细胞的细胞质小叶上氨基磷脂优先富集。氨基磷脂类似物的快速向内重新分布与所有三种精子细胞制剂中存在氨基磷脂转位酶活性一致。在精子附睾转运过程中，转位酶活性略有增强。然而，与附睾精子细胞相比，射出精子的氨基磷脂转位酶活性显著增加，且磷脂酰乙醇胺的磷脂不对称性更为明显。讨论了从公羊精子细胞质膜细胞外小叶快速去除氨基磷脂的生理相关性。通过细胞形态、膜完整性和细胞ATP浓度对精子细胞组分的质量进行了表征。
