Male-to-Female Transsexuals Show Sex-Atypical Hypothalamus Activation When Smelling Odorous Steroids
Link7/21/08
One working hypothesis behind transsexuality is that the normal sex
differentiation of certain hypothalamic networks is altered. We tested
this hypothesis by investigating the pattern of cerebral activation in
12 nonhomosexual male-to-female transsexuals (MFTRs) when smelling
4,16-androstadien-3-one (AND) and estra-1,3,5(10),16-tetraen-3-ol
(EST). These steroids are reported to activate the hypothalamic
networks in a sex-differentiated way. Like in female controls the
hypothalamus in MFTRs activated with AND, whereas smelling of EST
engaged the amygdala and piriform cortex. Male controls, on the other
hand, activated the hypothalamus with EST.