An autoradiographic study of the localization of androgen concentrating cells in the chaffinch

The distribution of labeled cells in the chaffinch brain has been examined by autoradiography after an intramuscular injection of [³H]testosterone. In the telencephalon labeled cells were particularly concentrated in nucleus magnocellularis neostriatalis anterioris, nucleus septalis lateralis, and hyperstriatum ventrale, pars caudale. In the diencephalon the nucleus periventricularis magnocellularis, the nucleus magnocellularis posterioris and the area infundibularis contained many heavily labeled cells. In the mesencephalon and medulla, labeled cells were found in the nucleus intercollicularis and in the nucleus nervi hypoglossi, respectively. Measurements of the density of grains per cell revealed (1) clear quantitative differences in the extent of labeling in different regions of the brain and (2) a wide variation in the density of labeling of individual cells within a region.The relationship between these sites of hormone binding and known sites of androgen action in the avian brain is discussed.