Changes in the distribution of filipin-sterol complexes in the boar sperm head plasma membrane during epididymal maturation and in the uterus
Article first published online: 26 JAN 2005
Copyright © 1992 Wiley-Liss, Inc.
The Anatomical Record
Volume 232, Issue 2, pages 221–230, February 1992
How to Cite
Seki, N., Toyama, Y. and Nagano, T. (1992), Changes in the distribution of filipin-sterol complexes in the boar sperm head plasma membrane during epididymal maturation and in the uterus. Anat. Rec., 232: 221–230. doi: 10.1002/ar.1092320207
- Issue published online: 26 JAN 2005
- Article first published online: 26 JAN 2005
- Manuscript Accepted: 19 JUN 1991
- Manuscript Received: 3 DEC 1990
The distribution of filipin-sterol complexes (FSCs) and intramembranous particles (IMPs) in the plasma membrane of the late spermatid of the boar and of the sperm obtained from the epididymides, ejaculates, and uterus 2 hours after mating was examined by a freeze-fracture replica technique. In the late spermatid, the FSC density was found to be very low. A majority of the FSCs in the acrosomal plasma membrane (APM) appeared as protuberances on the E face in the epididymal, ejaculate, and uterine sperm. The density of the FSCs in the principal segment (PS) of the APM was 291 ± 44 FSC/μm2 (mean ± standard deviation, S. D. ), 322 ± 41 FSC/μm2 and 355 ± 31 FSC/μm2 in the caput, corpus, and cauda epididymidis, respectively. In comparison with the cauda epididymal sperm, the FSC density gradually decreased in the PS of the ejaculated (277 ± 39 FSC/μm2) and uterine sperm (243 ± 50 FSC/μm2). The reduction was especially remarkable in the equatorial segment (ES), where the density of FSCs in ejaculated and uterine sperm decreased to about half and less than half of that in the cauda epididymal sperm, respectively.
Large (13 nm) and small (8 nm) IMPs were distributed evenly and densely in the P face of the APM in the late spermatid, epididymal, and ejaculated sperm. In the uterine sperm, IMP-free areas were observed in the P face of the plasma membrane, a feature thought to represent one of the capacitation changes of the boar sperm.