Anatomical distribution of estrogen target cells in the avian CNS: a comparison with the mammalian CNS.

The distribution of labeled cells was investigated in the brain of the ring dove one hour after administration of 3H-estradiol. Major areas of concentration of labeled cells were found in (1) the preoptico-strial region: nucleus preopticus medialis and nucleus interstitialis of the dorsal olfactory projection, (2) the basal hypothalamic region: nucleus hypothalamicus posterior medialis and nucleus inferior, (3) the amygdaloid region: nucleus taeniae and adjacent portions of the archistriatum, and (4) the midbrain: substantia grisea surrounding the nucleus mesencephalicus lateralis, pars dorsalis. The findings support the phylogenetic homologies between the avian nucleus interstitialis of the dorsal olfactory projection and the mammalian nucleus interstitialis of the stria terminalis, the avian nucleus hypothalamicus posterior medialis and the mammalian nucleus ventromedialis hypothalami, as well as the avian nucleus inferior and the mammalian nucleus infundibularis-premammillaris ventralis. The results also suggest that the nucleus medialis and other more differentiated labeled areas of the mammalian amygdala.