Anandamide modulates the expression of GnRH-II and GnRHRs in frog, Rana esculenta, diencephalon

► Rana esculenta brain expresses two GnRH molecular forms and three GnRH receptors at least. ► The endocannabinoid anandamide decreases GnRH-I and GnRH-II expression. ► Anandamide upregulates GnRHR-I and GnRHR-II expression. ► Besides GnRH-I, it is shown for the first time that endocannabinoids modulate GnRH-II activity in vertebrates.