Widespread increases of cortical serotonin type 2A receptor availability after hormone therapy in euthymic postmenopausal women.

Objective: To use statistical parametric mapping to determine the extent of previously reported serotonin type 2A (5HT(2A)) receptor binding potential (BP) increases in postmenopausal women following hormone therapy.

Design: Repeated measures positron emission tomography (PET) study.

Setting: Academic research environment.

Patient(s): Five healthy, postmenopausal women.

Intervention(s): Serial PET images of [(18)F]altanserin uptake were acquired to measure 5HT(2A) receptor BP at menopausal baseline, following estradiol (E(2)), and following combined E(2) + micronized progesterone (P(4)).

Main Outcome Measure(s): 5HT(2A) receptor BP.

Result(s): Combined E(2) + P(4) treatment was associated with significant increases in the 5HT(2A) receptor BP increases in widespread areas of cerebral cortex. Treatment with E(2) alone was also associated with widespread cortical BP increases, although these changes reached statistical significance in fewer regions. The rate of [(18)F]altanserin metabolism was significantly decreased in the E(2) + P(4) condition relative to menopausal baseline, but this difference did not appear to correlate with changes in 5HT(2A) receptor BP.

Conclusion(s): Estradiol priming followed by combined E(2) + P(4) is associated with widespread increases in 5HT(2A) receptor BP in the cerebral cortex, consistent with the E(2)-associated increases in 5HT(2A) receptor density previously observed in experimental animals.