RT Journal Article SR Electronic T1 PET of Aromatase in Gastric Parietal Cells Using 11C-Vorozole JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1964 OP 1969 DO 10.2967/jnumed.110.087072 VO 52 IS 12 A1 Makoto Ozawa A1 Kayo Takahashi A1 Ko-hei Akazawa A1 Tadayuki Takashima A1 Hiroko Nagata A1 Hisashi Doi A1 Takamitsu Hosoya A1 Yasuhiro Wada A1 Yilong Cui A1 Yosky Kataoka A1 Yasuyoshi Watanabe YR 2011 UL http://jnm.snmjournals.org/content/52/12/1964.abstract AB Aromatase is a rate-limiting enzyme for estrogen biosynthesis and has been implicated in pathophysiological states of various diseases via estrogen production. This enzyme is known to be widely distributed in extragonadal and gonadal tissues including the stomach. In contrast to circulating estrogen, the functional role of gastric aromatase/estrogen has not been elucidated in detail, because there is no efficient methodology to investigate spatiotemporal changes of gastric aromatase/estrogen in vivo. Recently, (S)-11C-6-[(4-chlorophenyl)(1H-1,2,4-triazole-1-yl)methyl]-1-methyl-1H-benzotriazole (11C-labeled vorozole), based on a potent nonsteroidal aromatase inhibitor, has been developed as a tracer to investigate aromatase distribution in living animals and humans using a noninvasive PET technique. In the present study, we investigated gastric aromatase expression by means of PET with 11C-vorozole. Methods: After bolus injection of 11C-vorozole into the tail vein, emission scans were obtained for 90 min on male and female rats under isoflurane anesthesia. Displacement studies with unlabeled vorozole and autoradiographic analysis were conducted for demonstration of specific binding. Immunohistochemistry was performed to confirm aromatase expression. Results: PET scans revealed that 11C-vorozole highly accumulated in the stomach and adrenal glands. Displacement studies and autoradiography demonstrated that aromatase was expressed in the stomach but that the accumulation of 11C-vorozole in the adrenal glands might be through nonspecific binding. Immunohistochemical analysis revealed that aromatase is expressed in gastric parietal cells but not in adrenal glands. Moreover, the accumulation of 11C-vorozole in the stomach was significantly increased in fatigued rats. Conclusion: These results suggest that the 11C-vorozole PET technique is a useful tool for evaluation of gastric aromatase dynamics in vivo, which may provide important information for understanding the molecular mechanisms of gastric aromatase/estrogen–related pathophysiological processes and for the development of new drugs.