Brain differences in sheep linked to sexual partner ...( ned that the volume of the sexually dim...),Health

The sexually dimorphic nucleus was measured by examining the extent and level of expression of aromatase, a key enzyme in a hormonal pathway that is involved in the development and maintenance of masculine characteristics. Additional groups of neurons within the hypothalamus thought to be involved in other aspects of sexual behavior were analyzed for size differences. These groups of neurons were shown to be different in rams and ewes, and not different in the two groups of rams.

The goal of these studies is to further understand the biological basis of sexual behaviors. More specifically, researchers are trying to determine the role of brain anatomy and physiology in the expression and development of sexual behaviors and traits. The researchers believe the sheep animal model may also help provide answers about other brain-linked sexual functions.

"Future studies will address functional aspects of the observed differences in the hypothalamus and test the hypothesis that differences in brain anatomy and sexual partner preference arise as a consequence of hormone exposure during fetal development," said Charles Roselli, Ph.D., professor of physiology and pharmacology in the OHSU School of Medicine and senior author of the paper. "While we realize that sexuality is more complex in humans than reproductive behaviors in sheep, this model will help illuminate the basic principles that apply to all mammals, and may be helpful in understanding the biology of human behaviors as well."

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Contact: Jim Newman
newmanj@ohsu.edu
503-494-8231
Oregon Health & Science University
4-Nov-2002