Department of Anatomy, University of Helsinki, Finland
(Received 21st October 1974)
The fluid transporting spermatozoa out of the testis through the epididymis is known to undergo many changes. About 50% of the fluid secreted by the seminiferous tubules is reabsorbed by the first part of the epididymal duct system (Crabo & Gustafsson, 1964; Levine & Marsh, 1971). Between the caput epididymidis and the ductus deferens, a further 50% of the remaining fluid is reabsorbed.
Seminiferous tubule fluid and rete testis fluid contain several protein fractions not seen in the serum, as has been shown by polyacrylamide gel electrophoresis (Kormano, Koskimies & Hunter, 1971; Koskimies & Kormano, 1973). The fate and significance of most of these proteins is unknown. Recently, it has been shown electrophoretically that bovine epididymal plasma from the cauda region contains at least three proteins not detected in the rete testis fluid or serum (Amann, Killian & Benton,