IMPAIRMENT OF FOLLICULAR DEVELOPMENT BY INTRAOVARIAN INFUSION OF GONADOTROPIN-RELEASING-HORMONE ANTISERUM IN PREPUBERTAL PIGS

Antiserum against gonadotrophin-releasing hormone (GnRH) was infused into one ovary in 4 prepubertal gilts and control porcine serum was infused into one ovary in 4 other gilts. Ovaries were infused for 156 h, after which infused and non-infused ovaries were removed surgically and processed for histology. Infusion of GnRH antibodies did not alter(P > 0.10) concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH) or oestradiol-17-beta, and GnRH titres in peripheral circulation were low, averaging 1:15. Weights of ovaries not infused were similar (P > 0.10) between treatment groups. There were fewer (P < 0.05) follicles > 0.5 mm in diameter in the ovaries infused with GnRH antiserum than in the others, but there were no differences (P > 0.10) between treatment groups in the number of follicles < 0.5 mm in diameter. Infusion of GnRH antibodies increased (P < 0.05) the incidence of atresia in follicles with > 4 layers of granulosa cells compared with the other treatment groups. These results provide evidence that a peptide binding to the GnRH antibodies is involved directly in ovarian follicular development.