CHARACTERIZATION OF PROTEINS IN THE SEMINAL PLASMA OF STALLIONS, GELDINGS AND GELDINGS SUPPLEMENTED WITH TESTOSTERONE

The major proteins in stallion seminal plasma were characterised by tw o-dimensional polyacrylamide gel electrophoresis, and compared with th e patterns of proteins in normal geldings (castrated males) and geldin gs supplemented with testosterone. The major proteins or groups of pro teins identified according to their approximate relative molecular wei ght in kilodaltons (kDa) and apparent isoelectric point (pl) were: 1) 60 kDa, pl 7; 2) 23 kDa, pl 4-5; 3) 25-30 kDa, pl 5.5-6; 4) 23 kDa, pl 7-8; and 5) 15-20 kDa, pl 6-7.5. Protein groups 1 and 2 were more pro minent in the seminal plasma from the stallions and supplemented geldi ngs than that from the unsupplemented geldings, while protein groups 3 , 4 and 5 were more prominent in the seminal plasma from the unsupplem ented geldings.