Recent studies by us and others show that in addition to the well established peptide – steroid driven hypothalamo-pituitary-gonadal axis, a local control mechanism at the gonadal level play a pivotal role in activity of developing follicles as well as luteal cells. We suggest that the local control mechanism is highly responsive to metabolic and seasonal signals, determining the quality and eventually the fate of a mammalian oocyte and embryo. Transcription factors such as GATA 4 and 6 are known to be expressed in reproductive organs, especially the gonads. GATA4 was first detected in the mouse coelomic epithelium and porcine urogenital ridge of both XX and XY embryos. The role of GATA factors and their cofactors have been studied in ovarian pathology such as ovarian tumors, whereas some others like the cystic ovarian disease remains to be studied. Little is known about the responsiveness of these factors to metabolic challenges such as lactation and seasonal infertility. This project aims at using a novel ultra sound guided sampling technique (ULMU), which will allow repeated tissue sampling of the female ovary. This technique will be applied in the pig in order to study the local control mechanisms on the ovary, such as GATA transcription factor family members GATA-4 & GATA-6 and their cofactors like FOG-2. These factors are known to participate in transcription of proteins that are of essential significance regarding the follicular growth and function of corpora lutea. The activity of these factors will be followed through the breeding season and into seasonal infertility. In addition, the ULMU technique will be used to study the relationship between the energy reserves of the body during lactation, the respective response by the local control mechanism and subsequent ovarian function. This will be carried out by measuring metabolic markers such as the insulin like growth factor IGF I and free fatty acids in the follicular fluid and transcription factors in the follicle. The present research is intended to improve the understanding of local control mechanism of the female gonads as well as how the changes in season and the body metabolism are transferred to the immediate environment of the developing ovum and fertilized ova.
|Effective start/end date||01/01/2011 → …|