ANCILLARY FOLLICLE AND SECONDARY CORPORA-LUTEA FORMATION FOLLOWING EXOGENOUS GONADOTROPIN TREATMENT IN THE DOMESTIC CAT AND EFFECT OF PASSIVE TRANSFER OF GONADOTROPIN-NEUTRALIZING ANTISERA

A combination regimen of equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG) was used to stimulate ovarian follicular development in domestic cats. The rate of elimination of eCG from cir culation was estimated, and, following follicular aspiration, the form ation of ancillary follicles and secondary CL was characterized. The e ffect of gonadotropin-neutralizing antisera on the development of seco ndary ovarian structures, CL function and humoral immune responses als o was evaluated. After intramuscular injection, initial serum eCG conc entrations were variable, with the elimination half-life estimated at 39 to 55 h and eCG persisting in circulation for several days. Followi ng follicular aspiration, queens formed CL equal to the number of aspi rated follicles and exhibited a rapid increase in progesterone concent ration but developed high numbers of ancillary follicles by 5 d post a spiration. By 15 d post aspiration, all ancillary follicles had lutein ized to form secondary CL. Treatment with neutralizing antisera at the time of follicular aspiration slowed (P<0,05) CL formation but did no t decrease (P>0.05) the number of ancillary follicles or secondary CL. Progesterone concentrations did not differ (P>0.05) from control quee ns while secondary humoral immune responses to eCG were qualitatively similar between groups. In summary, eCG was eliminated slowly from cat s following intramuscular injection and this persistence in circulatio n may have contributed to the development of ancillary follicles and s econdary CL. However, the administration of neutralizing antisera at t he time of follicular aspiration was ineffective in preventing the for mation of these secondary ovarian structures.