TYPE-1 ANGIOTENSIN-II RECEPTORS IN RAT AND HUMAN SPERM

The physiological factors which induce and maintain mammalian sperm ma turation and motility generally remain unclear, although several agent s are known to be involved. We describe here the application of immuno cytochemical and immunoblotting methods to identify the angiotensin II type 1 (AT1) receptor in the tails of ejaculated rat and human sperm. Motility data on stimulated and unstimulated sperm from volunteers an d patients attending fertility clinics showed that angiotensin II may increase both the percentage of motile sperm and their linear velocity , while the specific AT1 receptor antagonist DuP753 inhibited the acti on of angiotensin II on the percentage of motile sperm. In rat seminif erous tubules, AT1 receptors were present in primary spermatogonia and in spermatid tails, but immunoreactivity was not seen in sperm contai ned in caput or cauda epididymis, showing that AT1 receptor function i s regulated during transit through the reproductive tract. Since local tissue renin-angiotensin systems are present in both male and female tracts, the data suggest that angiotensin II has a role in the mainten ance of sperm function and fertility.