“…Although the classical mechanism of action of GnRH implies stimulation of adenylate cyclase and cAMP production [Leung and Steele, 1992], the regulation of steroidogenesis by GnRH may be exerted through the stimulation of multiple pathways. The activation of PLCs and intracellular calcium increases have been involved in the action of gonadotropins in the ovary in several species, including the mouse, swine, hen and cow [Asem et al, 1987;Davis et al, 1987;Flores et al, 1991;Gudermann et al, 1992]. In other species, such as sheep and rats, GnRH did not induce calcium transients in the ovary [Davis et al, 1986;Wang et al, 1989;Wiltbank et al, 1989], although increases in InsP 3 formation after GnRH treatment were observed in these species [Jacobs et al, 1991;Davis et al, 1989].…”