Changes in lipase and phosphatase activities of rat spermatozoa in transit from the caput to the cauda epididymidis

Rat spermatozoa from the cauda epididymidis, freed from their cytoplasmic droplets and acrosomes, were found to have a lower lipid content and to incorporate [14C]glucose into their glycerides and glycerophosphatides at a lower rate than spermatozoa from the caput epididymidis. Against the background of the activities of some glycolytic enzymes which remained constant the activity of alkaline phosphatase decreased in spermatozoa migrating through the epididymis, whereas the activity of monoglyceride lipase increased. The corresponding enzyme activities of non-flagellate germ cells of the testis were measured for comparison. The triglyceride lipase of non-flagellate germ cells and of spermatozoa from both caput and cauda epididymidis was activated by cyclic 3':5'-AMP.