[Control of terminal follicular maturation during the follicular phase in domestic mammals]

Terminal follicular maturation in the ovine and the bovine species involves growth and differentiation processes in follicles between 1-2 mm diameter and the preovulatory stage. During this maturation, the follicle acquires the ability to ovulate and the oocyte becomes able to be fertilized and to develop after fertilization. Selection of ovulatory follicles results from the integration of different parameters such as the circulating levels of gonadotropins, the structure of follicular populations and the sensitivity of the hypothalamo-pituitary axis to ovarian hormones. Differences between follicles for FSH and LH responsiveness can be amplified by paracrine intrafollicular regulations. These mechanisms are probably determinant for selection of ovulatory follicles.