Women suffering from polycystic ovary syndrome (PCOS) show elevated levels of testosterone and testosterone derivatives in their systems, as well as an increased risk of anxiety and depression. As the offspring of these women (both sons and daughters) show similar symptoms, it's been believed that PCOS can be transmitted through genetic code. However, a new idea comes to question this -- specifically, the fact that the fetuses of mothers with PCOS are gestating in high levels of testosterone is what causes these symptoms.
High levels of maternal testosterone during gestation are known to affect brain morphology and function in offspring and research has been able to link it to feelings of anxiety in both mice and humans. An international team of researchers studied the levels of androgen receptors in different brain regions associated with anxiety and depression to find out exactly how maternal testosterone and anxiety are linked.
The offspring of rats that showed elevated levels of testosterone were anxious, with behavior indicative of this much more pronounced in female baby rats than male babies. The team found that the excess testosterone during gestation diminished the ability of the child to respond to the hormone -- much like how you stop registering smell or taste if it persists for too long.
Messenger RNA levels (that encode testosterone receptors information and other similar molecules) were lower in the amygdalae and hippocampuses of the offspring, with a stronger effect on the females. The amygdala in particular has an important role to play in processing emotions, and dysfunctionalities here have been linked with several anxiety disorders.
To confirm that testosterone can have these effects, the researchers recapitulated both the anxiety and the diminished receptor levels in adult female mice by injecting them with testosterone.
“The maternal testosterone dose used may masculinize the brain of female offspring,” the authors conclude about their rat model.
But it's not just a masculinization -- levels of a serotonin receptors were similar in the amygdalae and hippocampuses of testosterone treated mice of both sexes, but less than those of the control group.
This suggests that high testosterone levels in women suffering from PCOS during gestation cause anxiety in two generations. It makes the females themselves anxious, and it can alter the brain morphology of offspring, leading to anxiety disorders. And while the children do not inherit the higher level of testosterone in their system, they show less receptors for the hormone in their brain, influencing their behavious.
This is a level of transmission that is not genetic, but it's clearly inheritable.
