[Changes in ovarian activity after superovulation treatment in sheep].

Field: Veterinary (Health Sciences)

Serine proteases are involved in a number of biological processes requiring degradation of intracellular matrices in tissue growing and its rebuilding. These are situations during the growth and maturing of ovarian follicles and their conversion into corpus luteum. Trypsin activity of similar serine proteases are controlled by their inhibitors whose synthesis and secretion is regulated by endocrine, paracrine as well as autocrine mechanisms. The fertility in natural ovarian cycle is ensured by the balance between a number of factors. After superovulatory stimulations this balance is impaired to a different degree. The presented study has been aimed at the investigations of the effect of various combinations of serum gonadotropins (PMSG, Antex Leo, Denmark), choriongonadotropins (hCG, Praedyn, Léciva Praha, CR), follicle-stimulating hormone (FSH, Foliocotropin, Spofa, Léciva Praha, CR) and anti-PMSG (goats antiserum against PMSG, Bioveta Ivanovice, CR) administered in the oestrum period after synchronization (12 days) by Agelin vaginal sponges (20 mg of chlorosuperlutine per animal; Galena Komárov, SR) on changes of some reproduction characteristics in ovaries and levels of catecholamines in follicular fluid. Changes in the ovarian weight were statistically significant in groups after administration of combined PMSG + hCG (750 + 750 IU; p < 0.01), PMSG + hCG + anti-PMSG (750 + 750 + 5 ml; p < 0.02) doses of hormones and FSH (2 x 80 + 2 x 80 + 1 x 40 + 1 x 40 IU; p < 0.01) during 4 days. Average numbers of prominating follicles and trypsin-inhibitory activity (TIA) values of their follicular fluid (FT) were influenced by LH component of stimulating hormones what was, on the contrary, manifested as by occurrence of the category of follicles over 10 mm as by their significantly higher TIA FT (p < 0.01). In as much as mean values of TIA blood plasma which were on average 10 times lower than in FT, were changed in a different way, it is supposed that synthesis and secretion of TIA in FT is affected by local mechanisms (Gosden et al., 1988; Smokovitis et al., 1988; Monget et al., 1996). It follows from studies of the used hormonal preparations on levels of catecholamines in ovine follicular fluid that DA and NE concentrations changed in dependence on the superovulatory stimulation used. Administration of PMSG (1000 IU) resulted in significant decrease of DA levels (p < 0.01) and EPI (p < 0.05) in ovine follicular fluid. Anti-PMSG serum application partially modified the DA and EPI levels to those of the control group. After hormonal stimulation by PMSG and hCG different effect has been observed. Antisergon application after the given combination of hormones had no effect on the EPI and NE levels in ovine follicular fluid but resulted in the increase of DA content (p < 0.05). The most conspicuous effect on the catecholamine level in follicular fluid was induced by FSH after which follows a marked increase of DA (p < 0.01) and NE (p < 0.01) levels. Similar significant effect of FSH on the change of catecholamine levels and on MAO activity in reproductory organs of sheep and in regulatory regions of reproduction were recorded in our previous contributions.