Origin of the luminal fluid proteins of the rat epididymis.
Using a combined microperfusion and high resolution gel electrophoresis technique, the origin of the epididymal fluid proteins of the rats has been investigated. Some proteins originate from the testis, others are secreted by the epididymis or are released by spermatozoa. Of particular interest is a 32 000 dalton protein found to be actively secreted by the caput epithelium in situ and concentrated in the lumen. The cauda epididymis contained the highest concentration of this protein. Radioactive labelling of the sperm surface proteins revealed that this protein was present on the surface of the mature cauda but not on the immature caput or corpus sperm, suggesting its acquisition by the sperm surface during epididymal transit. Another sperm surface protein of interest (MW 40 000) is present only on the plasma membrane of the cauda but not on that of the caput or corpus sperm. Since this protein was not identified in the epididymal perfusates or luminal fluids, its presence may result from some modification events taking place in the sperm membrane during maturation.
D000818:Animals; D001798:Blood Proteins / Q000378:metabolism; D001826:Body Fluids / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004822:Epididymis / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D008970:Molecular Weight; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D012671:Seminiferous Tubules / Q000378:metabolism; D013094:Spermatozoa / Q000378:metabolism
D001798:Blood Proteins; D008565:Membrane Proteins; D011506:Proteins