Further, ovine FSH injected to laying hens was able to stimulate P4 production by granulosa cells of F3 and F4 follicles in vitro ( Hertelendy et al., 1982). Moreover, FSH induces the expression of P450scc (cholesterol desmolase) and P45017c (17α-hydroxylase) mRNAs in granulosa cells for the onset of P4 production ( You et al., 1996 and Hernandez and Bahr, 2003).