Brain/metabolism; Coturnix/physiology; Gonadotropin-Releasing Hormone/analogs & derivatives; Gonadotropin-Releasing Hormone/immunology; Gonadotropin-Releasing Hormone/metabolism; Hypothalamus/cytology; Hypothalamus/immunology; Hypothalamus/metabolism; Immunohistochemistry; Median Eminence/innervation; Neurons/cytology; Neurons/immunology; Neurons/metabolism; Nucleus Accumbens/cytology; Nucleus Accumbens/immunology; Nucleus Accumbens/metabolism; Photoperiod; Pituitary Gland, Posterior/cytology; Pituitary Gland, Posterior/immunology; Pituitary Gland, Posterior/metabolism; Reproduction/physiology; Testis/anatomy & histology; Tissue Distribution/immunology; Vasoactive Intestinal Peptide/immunology; Vasoactive Intestinal Peptide/metabolism; Animals; Brain/anatomy & histology; Brain/immunology; Light; Male; Sexual Maturation