Sex hormones appear to act on the developing brain to distinguish male and female "types," Geoffrey W. Harris, MD, said in delivering the second annual Upjohn lecture at the Endocrine Society's 46th meeting in San Francisco in June.
In addition, Harris said, investigation may reveal effects of other hormones on the developing mammalian brain.
Harris, who is Lee's Professor of Human Anatomy at Oxford University, and honorary director of the British Medical Research Council Unit of Neuroendocrinology, said that the sex hormones seem to exert a double action on the mammalian central nervous system (CNS).
First, during fetal or neonatal life, the hormones appear to act in an inductive manner on the undifferentiated brain, as they do on the undifferentiated genital tract, to organize it into a male or female type. Second, during adulthood, the gonadal hormones exert excitatory or inhibitory actions on the CNS, and are thus concerned with