According to a study presented at the 35th ECNP Congress held in Vienna, the amount of nicotine in one cigarette inhibits women’s brains from producing estrogen. The researchers explained that this may explain a variety of behavioral differences in smokers, including the reason why women have a higher resistance to quitting than males.

In the study, 10 healthy female volunteers received an intranasal dose of nicotine from a commercial source. The participants also received an injection of a radioactive tracer bound to an enzyme called aromatase, also known as estrogen synthase, which binds to estrogen. Using MRI and PET brain images, the researchers were able to visualize the amount of aromatase present in the brain.

The researchers discovered that a single dose of nicotine slightly decreased the brain-based aromatase level. However, they stated that it was unclear what biological factors led to these variations. This is the first instance where the production of aromatase has been inhibited in humans. They added that the findings of the study led them to believe that nicotine’s effect on estrogen production has a significant impact on the brain but perhaps also on other functions, such as the reproductive system.

The researchers noted that there are significant differences in the way men and women react to smoking, such as women are more resistant to nicotine replacement therapy, experience more relapses, show greater vulnerability to the heritability of smoking, and are at greater risk of developing primary smoking-related illnesses, namely lung cancer and heart attacks. 

(Source: https://theprint.in/health/nicotine-dose-in-one-cigarette-blocks-estrogen-production-in-womens-brains-study/1170941/ )