The present study was undertaken to clarify the role played by protein binding substances in the dynamics of gonadotrophins during the estrous cycle in rats. The results indicated that the half life (
tn) of both PMSG and hcGestrous-rats were shorter than in diestrus ones. Inject ion of both albumin and globulin fractions obtained from diestrus rats into estrous ones prolonged the taso of both PMSG and hcG. During diestrous the half-life of hcg was proplonged in rats treated with albumin or globulin obtained from estrous-ones.
The half-life of PMSG in diestrous-rats treated with globulin-fraction obtained from estrous-ones was similar to its to join estrous-rats. In addition albumin fraction obtained from estrous-rats when administe red into diestrous-ones led to a decrease in tio of PMSG but not as in case of globulin.
Thus we can conclude that protein binding substances may play an important role in the dynamics of gonadotrophins especially PMSG during estrous phase.