Changes in Antiproteolytic Activities of Blood-Plasma and Follicular-Fluid of Ovaries in Ewes of 3 Breeds After Superovulation Stimulations

Veterinarni Medicina 36, 1991, 539-549

Serine proteases help to regulate the ovarian cycle at different levels and they are subjected to the control of gonadotropic hormones and protease inhibitors. Superovulation stimulations influence the activities of trypsin inhibitors (model serine protease) in blood plasma (BP) and in follicular fluid (FF), and also in dependence on the breed. Trypsin inhibiting activities were determined from the reduced rate of trypsin hydrolysis of a chromogenic substrate (TAPA) and they were determined in percent. A change in absorbancy at 405 nm = 1.0 after 10-minute incubation at 25-degrees-C and pH = = 8.05 was taken as 100 %. The incubation mixture as a sample contained 100-mu-l blood plasma or 10-mu-l follicular fluid, diluted with gammaglobulin at 1:10. The differences in the trypsin inhibiting activities (TIA) of BP in ewes of the Merino, Tsigai and Wallachian breeds were insignificant, but Agelin synchronization (20 mg chlorsuperlutin per vaginal swab) induced statistically significant differences. The lowest TIA BP was recorded in the Tsigai breed (T), P < 0.001 in comparison with the Wallachian (W) and Merino (M) breeds. Following the administration of 1 500 IU PMSG, the TIA BP within 120 hours decreased in W (P < 0.001), it increased in T (P < 0.1) and in M the changes in the TIA BP were insignificant (Fig. 1). The average numbers of ovulations increased from 2.25 +/- 2.5 to 3.0 +/- 1.2 in W

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