Role of Granulosa and Theca Cells on in Vitro Progesterone Production in Preovulatory Follicles of the Japanese Quail

The preovulatory follicles of the mature domestic birds are arranged in a distinct hierarchical order in the ovary. Presumably all preovulatory follicles are exposed to a daily surge of luteinizing hormone (LH), but only the largest follicle (F1) ovulates each day. This has been explained by the ability of progesterone synthesis of F1 in response to LH. In fact, progesterone contents in the follicle wall of F1, but not of the second largest (F2) or the third largest (F3) follicle, increased concomitantly with the raise of serum LH1,2). Even though the concentrations of LH were not significantly different among venous plasma of various sizes of follicles, only the venous plasma of F1 exhibited the preovulatory peak of