Evidence of intraovarian follicular dominance effects during controlled ovarian stimulation in a sheep model.
OBJECTIVE
To evaluate intraovarian dominance effects in a sheep model and to determine whether local factors, independent of FSH-mediated pathways, are capable of interfering with the final development of subordinate follicles.


METHODS
Observational, model study.


METHODS
Public research unit.


METHODS
Three hundred sixty-four adult Manchega ewes.


METHODS
Synchronization of estrous cycle with intravaginal progestogens and ovarian stimulation with FSH; ovarian ultrasonography, laparoscopies, and embryo recoveries.


METHODS
Determination of morphological characteristics and developmental competence of ovarian follicles.


RESULTS
The presence of a dominant follicle affects number and viability of embryos from the ipsilateral ovary in females that are treated with high FSH doses; this effect, modulated by season and phase of the estrous cycle, highlights the role of LH in follicular dominance.


CONCLUSIONS
The current study confirms, in a sheep model, the existence of local effects from dominant follicles over neighboring follicles, by direct action and independently from systemic pathways through FSH modulation.
Gonzalez-Bulnes
Antonio
A
Departamento de Reproduccion Animal, Instituto Nacional de Investigacion Agraria y Tecnologia Alimentaria (INIA), Madrid, Spain. bulnes@inia.es
Veiga-Lopez
Almudena
A
D000465:Algorithms; D000818:Animals; D001947:Breeding; D002470:Cell Survival; D002478:Cells, Cultured; D046149:Embryo Culture Techniques; D004622:Embryo, Mammalian; D005260:Female; D023421:Models, Animal; D008954:Models, Biological; D054315:Oocyte Retrieval; D006080:Ovarian Follicle / Q000033:anatomy & histology / Q000502:physiology*; D010062:Ovulation Induction; D011247:Pregnancy; D012098:Reproduction / Q000502:physiology; D012189:Retrospective Studies; D012756:Sheep