The total protein quantity of the different lanes analyzed by a digital system indicated that these proteins were less than 3% of the total protein of the caudal fluid. This value was similar to that obtained by the Bradford assay using BSA as the standard and was also demonstrated by the lack of difference in the pattern of proteins of the cauda fluid before (CEF) or after ultracentrifugation (CEF-hs).
Small Membraneous Vesicles Are Normal Constituents of the Epididymal Fluid
To ascertain that these vesicles had a physiological significance and were not artifacts induced by the collection method, we compared the pellet obtained with the seminal fluid of normal and vasectomized rams collected 3 mo after the surgery (no sperm could be observed in the ejaculate at this time). After high-speed centrifugation, seminal plasma from both types of animals yielded a pellet, but the pellet obtained from the vasectomized rams was much smaller than from the controls. After separation by SDS-PAGE (Fig. 3B), the protein pattern of vesicles obtained from the vasectomized animal was very different from that of the normal ram and that of the cauda epididymis.