Depending on where your head鈥檚 at, the phrase 鈥渂rain sex鈥� might not mean what you think. On the other hand, this week鈥檚 podcast is all about hormones. In our latest edition of At the Lab, we hear from CSHL Associate Professor Jessica Tollkuhn about the role of estrogen in brain development.
Read the related story: How hormones define brain sex differences
Transcript
Caroline Cosgrove: You鈥檙e now At the Lab with 黑料吃瓜资源. I鈥檓 Caroline Cosgrove and this week At the Lab, 鈥淏rain sex.鈥�
CC: When it comes to sex hormones, most people associate men with testosterone and women with estrogen. And there is some truth to that. But, according to CSHL neuroscientist Jessica Tollkuhn, the whole truth isn鈥檛 so black and white. In fact, it鈥檚 not really pink or blue, either. Here鈥檚 Tollkuhn:
Jessica Tollkuhn: A lot of people, even neuroscientists, are not familiar with this idea that in rodents, estrogen is actually masculinizing for the brain. This is really counterintuitive. The testes make testosterone. The ovaries make estradiol, which is the principal estrogen. But you can treat females with estradiol on the first day of birth, and they will grow up and will be territorial like the males. They still have female physiology. They鈥檙e still cycling. They can still have babies. But their brain is permanently masculinized by seeing estrogen early.
CC: This has been known for decades. What scientists didn鈥檛 understand is how a temporary hormone surge can have lifelong effects. Today鈥檚 advanced technologies have made it possible to see what鈥檚 going on at the cellular level. Tollkuhn鈥檚 team zeroed in on a particular part of the mouse brain and then went even deeper.
JT: So, there鈥檚 kind of two questions. Where are the hormone receptors binding? And then how does this relate to sex differences in the brain?
CC: Tollkun鈥檚 team was able to identify the specific genes under estrogen鈥檚 control, including many involved in brain development.
CC: Now she鈥檚 exploring the roles these genes play later in life. Her work may one day lead to new hormone replacement therapies or treatments for neurodegenerative diseases like Alzheimer鈥檚. But it鈥檚 also eye-opening in another way. It suggests that brain sex is the product of fluctuating hormones rather than unchanging sex chromosomes.
JT: If you consider that there鈥檚 variation in hormone receptors and hormone levels and the target genes of hormones just across individuals, then you can imagine there鈥檚 this whole rainbow of different ways that the brain can be differentiated. There鈥檚 always a question of what can we learn about ourselves? Where does personality come from? So yeah, I鈥檓 excited to keep working on hormones and how they affect different aspects of the brain.
CC: And we鈥檙e excited to see what she comes up with next, At the Lab.
CC: Thanks again for listening. If you like what you heard, please subscribe wherever you get your podcasts. And visit us at CSHL.edu to get more fascinating science stories like this one. For 黑料吃瓜资源, I鈥檓 Caroline Cosgrove. And I鈥檒l see you next time At the Lab.