EN
This study investigated the influence of active immunization against GnRH on the innervation of the prostate gland in pigs by means of immunohistochemical and quantitative methods. Three control groups of the animals including: Gl- 10 week-old, G2- 18 week-old, G3- 26 week-old and four groups of immunized pigs: G4, G5, G6 and G7 (from 7 to 9 animals in each group) were used. Immunization was accomplished by vaccination against GnRH with a vaccine purchased from the Peptech Animal Health, Australia. The pigs of G7 were immunized with the same peptide but suspended in a Freund's adjuvant. The presence of dopamine ß-hydroxylase (DßH), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY) and protein gene product 9.5 (PGP) within nerve fibres supplying the prostate gland in the intact animals and in boars undergoing the active immunization was studied using single-or double-labelling immunohistochemistry. Moreover, noradrenaline (NA), NPY and VIP concentrations were estimated in the body of the prostate gland with HPLC and RIA methods. Immunohistochemical studies showed that a density of DßH im- munoreactive (-IR) nerve fibres supplying the prostate in the pigs of G7 was significantly higher than that in the remaining groups. The density of PGP- and NPY-IR nerve fibres was higher after immunization in both immature (G4) and mature (G5, 6, 7) pigs than that in the control animals while the density of VIP-IR nerve fibres was very similar. The quantitative studies revealed that NA tissue concentration in the animals of G7 was significantly higher than that in the remaining groups while NPY tissue content was significantly higher in both immature (G4) and mature (G5, 6, 7) animals. The tissue concentration of VIP in all the immunized groups was similar to that observed in the control pigs. The present results show that the most effective immunization was achieved in the animals injected twice according to modified method with Freund's adjuvant (G7) and suggest that in the future, it could be considered as the alternative method of castration.