Acute effect of intranasal estrogen on cerebral and cerebellar perfusion in postmenopausal women

OBJECTIVES: Estrogen action in the brain influences many neurochemical processes. The aim of the study was to evaluate the acute effect of intranasal 17beta-estradiol on cerebral and cerebellar perfusion in postmenopausal women. METHODS: The study group included 24 healthy postmenopausal women who had been in natural menopause for at least 1 year (mean age: 47.38+/-5.9 years). We conducted an experimental, randomized, placebo-controlled, cross-over, double-blind study. Cerebral and cerebellar perfusion was measured after placebo (saline serum physiologic) or intranasal 17beta-estradiol administration by Single Photon Emission Computed Tomography (SPECT) using technetium-99m-hexamethylpropylene amine oxime (Tc99m-HMPAO). Regions of interest (ROIs) were drawn manually. Cerebral and cerebellar perfusions were calculated for each ROI using average number of counts per pixel. Semiquantitative analysis was performed in bilateral frontal, temporal, parietal and occipital lobes, thalamus, putamen, hippocampus, amygdala, caudate nuclei, cerebellar region, anterior/posterior of cingulate gyrus and pons. RESULTS: After intranasal 17beta-estradiol administration, SPECT study revealed significant increases in cerebral and cerebellar perfusion compared to placebo measurements in all studied slices (p<0.05). There was a positive correlation between serum estrogen levels after 17beta-estradiol and cerebral and cerebellar perfusion. CONCLUSIONS: Administration of single dose intranasal 17beta-estradiol increases cerebral and cerebellar perfusions in healthy postmenopausal women.