BOR - Papers in Press, published online ahead of print
October 4, 2002.
Biol Reprod 2002, 10.1095/biolreprod.102.006684
Biology of Reproduction 67, 1763-1767 (2002)
DOI: 10.1095/biolreprod.102.006684
© 2002 Society for the Study of Reproduction, Inc.
Germinal Angiotensin I-Converting Enzyme Is Totally Shed from the Rodent Sperm Membrane During Epididymal Maturation1
Sonia Métayera,
Françoise Dacheuxa,
Jean-Louis Dacheuxa, and
Jean-Luc Gatti2,a
a Equipe "Spermatozoïdes," UMR 6073 INRA-CNRS, Institut National de la Recherche Agronomique, Centre de Nouzilly, 37380 Monnaie, France
Acquisition of sperm fertilizing ability is due, in part, to the reorganization of plasma membrane proteins that occurs during epididymal sperm transit. Using polyclonal antibodies against angiotensin I-converting enzyme (ACE), we showed that this enzyme is immunolocalized mainly on the middle piece of rat and mouse testicular sperm and with less intensity along the initial part of the principal piece of the flagellum. In both species, only some sperm from the caput epididymis were still reactive, whereas no labeling was observed on cauda epididymal sperm. The 105- to 110-kDa germinal ACE was absent from the rat testicular fluid but appeared in the fluid of the anterior epididymis. Thereafter, its molecular weight shifted to 94 kDa in the corpus epididymal fluid and remained at this weight in the caudal region. The 105- to 110-kDa immunoreactive protein was present in testicular rat sperm extract but was completely absent from epididymal sperm extracts. Western blot analysis of testicular and epididymal tissue extracts from the rat and mouse also confirmed that the germinal enzyme was absent from the epididymal sperm cell. Our results demonstrated that the rodent germinal ACE is released from the testicular sperm membrane when sperm enter the epididymis, a process similar to that observed in domestic mammals. This result is discussed in view of the suggested role for this enzyme in sperm fertility.
1 Supported by a grant from "Biotechnocentre-Région Centre." S.M. was the holder of a thesis grant from "Région Centre."
2 Correspondence. FAX: 33 247 427 743; gatti{at}tours.inra.fr
Copyright © 2002 by the Society for the Study of Reproduction.