Changing your sex changes your brain: influences of testosterone and estrogen on adult human brain structure
- Hilleke E Hulshoff Pol,
- Peggy T Cohen-Kettenis1,
- Neeltje E M Van Haren,
- Jiska S Peper,
- Rachel G H Brans,
- Wiepke Cahn,
- Hugo G Schnack,
- Louis J G Gooren2 and
- René S Kahn
- Department of Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, A01.126, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands, 1Department of Medical Psychology and 2Department of Endocrinology, VU University Medical Center, Amsterdam, The Netherlands
- (Correspondence should be addressed to H E Hulshoff Pol; Email: h.e.hulshoff{at}azu.nl)
Abstract
Objective: Sex hormones are not only involved in the formation of reproductive organs, but also induce sexually-dimorphic brain development and organization. Cross-sex hormone administration to transsexuals provides a unique possibility to study the effects of sex steroids on brain morphology in young adulthood.
Methods: Magnetic resonance brain images were made prior to, and during, cross-sex hormone treatment to study the influence of anti-androgen + estrogen treatment on brain morphology in eight young adult male-to-female transsexual human subjects and of androgen treatment in six female-to-male transsexuals.
Results: Compared with controls, anti-androgen + estrogen treatment decreased brain volumes of male-to-female subjects towards female proportions, while androgen treatment in female-to-male subjects increased total brain and hypothalamus volumes towards male proportions.
Conclusions: The findings suggest that, throughout life, gonadal hormones remain essential for maintaining aspects of sex-specific differences in the human brain.
- Received 30 April 2006
- Accepted 7 July 2006
- © 2006 Society of the European Journal of Endocrinology
