All posts by Josien

I'm a Neuroscientist unravelling the effects of sex-hormones on the brain!

‘being hormonal’ is not a thing

Hi!

If you’re here you are either independently interested or had a throwing card chucked at you. If you have, I should admonish you for suggesting someone was being hormonal. But frankly, I’m kind of impressed that you came to check whether your convictions have any ground, so well done you!

I want you to know that even though we have a lot of anecdotal data about people turning into monsters at particular times of their menstrual cycles, adolescence or pregnancy, there is no known biological mechanism for how hormones should affect someone’s ability to be reasonable or nice.

It might well be the case that people go a bit weird when their hormone levels rise, but we don’t have good scientific behavioral evidence or any idea how that would work biologically.

If you’re happy to take my word for it, great! I am a neurobiologist and pretty trustworthy, you can go have an ice cream and enjoy your day. If not, I have outlined how I’ve come to my conclusions and how you can check your convictions next time so you don’t get stuff thrown at you.

Here we go

The pubmed search

If you want to know whether concept or a thought about physiology has any basis in science, your first port of call is either pubmed  orsciencedirect or if you must scopus.  They are the google of science. Yes I am aware that google scholar exists, but too often I have found complete non-science and nonsense when I’ve simply googled. Besides, this is what the real scientists use.

So you type in your keywords. The annoying thing is that you do have to use the scientific terms here. So I’ll allow a quick trip to Wikipedia to come up with the proper terms. If that fails, sometimes just googling your question plus ‘scientific terms’ may help. Mind you, even if you find a website that says your thing totally exists, if they don’t reference a proper scientific paper that you can then find on pubmed. It. Doesn’t. Count.

Ok, so in a bout of integrity, I am actually doing the thing I told you to do. I’m using the terms ‘mood’ and ‘cognition’ and ‘sex hormones’ to find out if anyone in the scientific community knows how a menstrual cycle can make someone grumpier or less reasonable.

pubmed results moodNow our first clue is that there is no paper on the first page of results that even has those words in the title. Now pubmed generally gives you most recent and relevant results but will tell you if there is a paper that has all the words you asked for in the title, even if it is really old. The fact that we have neither is telling. The most feasible option is number 6, which is a study in psychotic patients and finds effects only of male hormones; female hormones don’t even do anything in psychotic patients!

When you’re browsing these articles, it’s generally good to look for reviews. Reviews cover a whole lot of publications on a subject and summarize them. It is really important though, that when you find a review which mentions your thing, to always check the experimental work! So if you find a publication stating: “st. Claus et al (1980) found sex hormones affect cognition” make sure you check the paper mr. Claus et al published in 1980. Papers get misquoted all the time!

Back to our quest!

Read a review

So I had a bit of a rummage around and found this awesome review by dr. Pletzer

article cognition pletzerThe article is an extensive review of male and female cognition. Nowhere in the entire is article there an experimental study that shows how sex hormones affect cognition. In the end, the author can only conclude that it would be interesting to look at whether sex hormones can influence cognition and how they would do it.

This tells us a couple of things. One; this article was published, so other scientists have read it and thought it wasn’t nonsense. Two; it was published in frontiers of neuroscience, which means it’s not established knowledge. Three, there is only mention of hypotheses, which means that if the author had found anything to support them, she would have mentioned it. And I think we can all agree that she’s looked.

Careful with conclusions

It is the bane of science and sensible people in general that we want to be nuanced. That gets in the way of clear cut conclusions and snazzy one-liners. I mean, ‘ice cream makes you smart!’ sounds a hell of a lot better than: ‘glucose, a major component of many foodstuffs including ice cream, is a important source of ATP, which provides energy for certain specific processes in neurons, which is only one type of brain cell’.

A good scientist, or indeed a truthful person, outlines what he or she doesn’t know as well as what they do know. So , yes, we have some anecdotal data (which means it happened to you, your mom, a friend’s friend) on crazy ladies, adolescents and bodybuilders. There may even be some studies saying that there are definitely some distinct differences in behavior between the genders and people of different ages. Then we still don’t know if it’s necessarily their gender or age that’s making them crazy. As long as we have not shown in a well-controlled experiment that the thing that we think is doing the thing actually has that effect on the thing we say it’s doing it to, we cannot present it as a fact.

This means no telling people they’re ‘being hormonal’.

And really, that’s a dick move even if you do have the evidence. Why not just say: ‘would you like some chocolate?’ That always gets a smile.

PS: If you can find proper scientific research debunking any of the above, please let me know and I will alter the contant of this blog and if need be, my awesome throwing cards

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The science

Have you ever noticed that men and women are different? if you haven’t.. maybe go google that first (I am not taking responsibility for any disturbing images you might find). If you have, congratulations, you are now with me at the forefront of science.

We are finding out that men and women are different in the way they get sick. The kind of diseases they get, when they get them, even how long they live. What we don’t know, is why.

So, what makes us men and women in the first place?
Basically, our sex hormones.

So what do sex hormones do to the brain? We don’t know. And that’s what I want to find out.

Our group works on tryptophan metabolism. Tryptophan is an essential building block for our body’s molecules. We can’t produce it, we have to get it from our food.

(thankfully, this is delicious, we get tryptophan from cheese, eggs even asparagus!).

Tryptophan can be used in lots of ways, it can be a building block for serotonin, which influences your mood, or melatonin, which  influences sleep, it can be a source of energy for the immune system.. Or it can be turned into kynurenine and further metabolized in the kynurenine pathway.
The products of this pathway have effects on the immune system and on the brain (also, the immune system has a huge effect on the brain). We know that when people get sick, the activity of this pathway changes. We also know that in a lot of the diseases in which the pathway changes, there is a big gender difference. For instance, we know that the kynurenine pathway is changed in patients with Alzheimer’s disease. We also know that more men than women get Alzheimer’s. What we don’t know, is why.

There is quite a bit of evidence that the kynurenine pathway plays are part a lot of diseases. We also know that sex hormones and gender are a factor in these same diseases. What we need to know is how the two are connected.

I want to spend my waking hours finding out.

We need to know what sex hormones do to the kynurenine pathway in our brains. Not only to help develop treatments for when we’re sick, but to better understand what makes us tick.

This is work that needs to happen, but won’t without your support. Friend us on facebook, share our stuff, or donate if you can!

Why Genderbrain?

Even though we know that a lot of diseases affect men and women differently, most research is done in males. This means that effectively, women are medically treated as if they were men. By understanding the interactions of sex hormones with our physiology we can not only right a blatant wrong, we may also unlock a new mechanism for treatment.  Additionally, in medical research gender would go from being a ‘mysterious unknown to be avoided’, to a known factor to be incorporated to make for more complete and well-rounded studies.

Women are more likely to get depressions; men are more likely to get ALS and we don’t know why.  The biggest physiological differences between men and women are their sex hormones. Sex hormones are often blamed for mood swings and wild behaviour, but what do we really know about the effect of hormones on the brain?

I’m studying what hormones do to the metabolism of sick and healthy brain cells and what that means for treatment of mental health disorders in men and women. I study both brain cells and actual humans. come look gifMy early results are showing that oestrogen has an effect on a very important part of the metabolism of brain immune cells. This part is called the ‘kynurenine pathway’ and it produces molecules that communicate with both the immune system and other brain cells. When I looked at levels of these molecules in human samples, I found that they are different in men and women and that the differences are dependent on their sex hormone levels.

We know quite a bit about how mental disorders are different in men and women, but we really don’t know why. The metabolic pathway I study is involved in a lot of these disorders. Putting together the puzzle pieces of the kynurenine pathway and sex hormones will give us an idea of how they fit together to produce or prevent mental disorders. The kynurenine pathway is part of the metabolism of most cells in the body, so understanding this relationship may well prove important in the whole of medical research.