Nicotine blocks brain estrogen synthase (aromatase): in vivo positron emission tomography studies in female baboons.
BACKGROUND
Cigarette smoking and nicotine have complex effects on human physiology and behavior, including some effects similar to those elicited by inhibition of aromatase, the last enzyme in estrogen biosynthesis. We report the first in vivo primate study to determine whether there is a direct effect of nicotine administration on brain aromatase.


METHODS
Brain aromatase availability was examined with positron emission tomography and the selective aromatase inhibitor [(11)C]vorozole in six baboons before and after exposure to IV nicotine at .015 and .03 mg/kg.


RESULTS
Nicotine administration produced significant, dose-dependent reductions in [(11)C]vorozole binding. The amygdala and preoptic area showed the largest reductions. Plasma levels of nicotine and its major metabolite cotinine were similar to those found in cigarette smokers.


CONCLUSIONS
Nicotine interacts in vivo with primate brain aromatase in regions involved in mood, aggression, and sexual behavior.
Biegon
Anat
A
Brookhaven National Laboratory, Upton, New York, USA. biegon@bnl.gov
Kim
Sung-Won
SW
Logan
Jean
J
Hooker
Jacob M
JM
Muench
Lisa
L
Fowler
Joanna S
JS
D000818:Animals; D047072:Aromatase Inhibitors / Q000493:pharmacokinetics; D001921:Brain / Q000000981:diagnostic imaging / Q000187:drug effects / Q000201:enzymology*; D003627:Data Interpretation, Statistical; D004305:Dose-Response Relationship, Drug; D005260:Female; D007275:Injections, Intravenous; D008279:Magnetic Resonance Imaging; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D010215:Papio / Q000378:metabolism*; D049268:Positron-Emission Tomography; D014230:Triazoles / Q000493:pharmacokinetics
D047072:Aromatase Inhibitors; D018722:Nicotinic Agonists; D014230:Triazoles; C060523:vorozole; D009538:Nicotine