COMPARATIVE-STUDIES OF OVARIAN-STEROIDS IN BLOOD, AND SPECIFIC PROTEOLYTIC-ENZYMES IN THE CERVICAL-MUCUS, IN 4 SHEEP BREEDS AFTER ESTRUS SYNCHRONIZATION (PROGESTERONE AND PMSG) .2. BREED VARIATION OF PAA, PAI AND PI IN THE CERVICAL-MUCUS DURING NATURAL ESTRUS, SYNCHRONIZED ESTRUS, AND THE FIRST ESTRUS AFTER SYNCHRONIZED ESTRUS

Plasminogen-activator activity (PAA), plasminogen-activator inhibition (PAI), and plasmin inhibition (PI) were studied in the cervical mucus of four sheep breeds (Friesland, Chios, Serres, Karagouniki) during n atural oestrus, synchronized oestrus, and the first oestrus after sync hronized oestrus. PAA had increased by the middle of natural oestrus, but with some differences among the breeds studied. Oestrous synchroni zation disturbed PAA in the cervical mucus, depending again on the bre ed. This disturbance persisted during the first oestrus after the sync hronized oestrus in all breeds studied except Friesland. PAA in the ce rvical mucus of the ewe was due to both types of plasminogen activator (t-PA and u-PA). PAI in the cervical mucus had increased by the middl e and end of natural oestrus, depending on the breed. Oestrous synchro nization disturbed PAI, which was still the case even during the first oestrus after synchronized oestrus. PI had increased by the end of na tural oestrus with some differences among the breeds studied. In all b reeds studied, PI in the cervical mucus was disturbed during the synch ronized oestrus. This disturbance of PI persisted, more or less, durin g the first oestrus after synchronized oestrus in all breeds studied e xcept Friesland. Blood oestradiol-17 beta, in a quite limited range of concentrations dependent on the breed and the type of the oestrus, co uld positively affect PAA or PAI and negatively affect PI in the cervi cal mucus.