Autoradiographic studies with 3H dihydrotestosterone in the brain of sex reversed mice,heterozygous for androgen insensitive testicular feminization (Tfm)

Summary Specific binding sites for ³H dihydrotestosterone are demonstrated by autoradiography in brain nuclei of sex reversed mice heterozygous for testicular feminization (Tfm) which are phenotypically intersexes with testes and accessory sex glands that consist of a mosaic of androgen insensitive Tfm cells which lack specific dihydrotestosterone binding and androgen sensitive normal cells. The nuclear group evaluated include: nucleus (n.) septi lateralis, n. interstitialis striae terminalis, n. medialis amygdalae, the hypothalamic n. arcuatus, n. ventromedialis lateralis, n. premammillaris ventrialis, n. preopticus medialis, and nuclei of the cranial nerves VII, X, and XII. In the sex reversed males and the female, used as controls, the frequency of neurons with specific DHT binding show a distinct male-female difference in the caudal part of the arcuate nucleus. In the sex reversed Tfm heterozygotes, in all brain nuclei studied, the frequency of labeled neurons is reduced. The extent of reduction of androgen binding in the different brain nuclei varies among as well as within individual sex reversed Tfm heterozygotes, suggesting variations of the ratio of normal to Tfm neurons in sex reversed Tfm heterozygotes. The differentially reduced androgen binding of different brain systems corresponds to a differentially reduced androgen dependent behaviour reported in the literature.Supported by US PHS grant NSO9914 to W.E.S. and Deutsche Forschungsgemeinschaft Dr94/4 to U.D.. The work of Dr. Schleicher and his stay in Chapel Hill were sponsored by Studienstiftung des Deutschen Volkes and Boehringer-Ingelheim Fonds