MATURATION ANTIGENS PRESENT IN EPIDIDYMIS OF CYNOMOLGUS MONKEYS (MACACA-FASCICULARIS)

PROBLEM: The present study was carried out to evaluate the changes in morphology and motility of spermatozoa retrieved from different region s of the epididymis of the cynomolgus monkey. The role of the epididym is in sperm maturation is assessed by assaying protein synthesis withi n different regions of the epididymis and by correlating these with ch anges in spermatozoal membrane surface components. METHOD: Spermatozoa retrieved from proximal caput (CP), midcorpus (CO), and distal cauda (CD) were assessed by morphological evaluation and computerized motion analysis. Membrane surface proteins of spermatozoa of different epidi dymal regions were extracted and separated on SDS-PAGE. Protein synthe sis of different regions of the epididymis were assayed in vitro by [S -35]-methionine incorporation. RESULTS: Spermatozoa obtained from diff erent regions of the epididymis differed morphologically only in the l ocation of the cytoplasmic droplet. Specifically, from caput to corpus to cauda, sperm steadily exhibited a more distal cytoplasmic droplet. When the motion parameters of velocity and amplitude of the lateral h ead were examined, CP spermatozoa were not progressively motile, and p oor duration of movement was most noticeable for CO spermatozoa compar ed with CD spermatozoa. Membrane extracts from CP, CO, and CD epididym al monkey spermatozoa differed in only several protein bands. Three ma jor polypeptide bands (19, 30, and 60 kD) that were absent from CP spe rm were present in CO and CD sperm, with the latter showing increased intensity. Several polypeptides were lost from the sperm during epidid ymal transit: a 25-kD band was lost in CD sperm; and bands at 27 kD, 5 0-52 kD, and 90 kD were only present for CP sperm. Additionally, regio nal differences exist for proteins secreted by the cynomolgus monkey e pididymis. Proteins (15, 25 kD) were only secreted in the CP region; a 38-kD protein increased in intensity from the CP to CD regions, where as a 21-kD protein was absent from CD-secreted medium. CONCLUSION: The se preliminary findings permitted the identification of several ''matu rational antigens'' for cynomolgus monkey spermatozoa. Further charact erization of these antigens that are modified during epididymal transi t is warranted to determine their significance in the acquisition of p rogressive motility and fertilizing ability by epididymal spermatozoa.