TY - JOUR T1 - PET of Aromatase in Gastric Parietal Cells Using <sup>11</sup>C-Vorozole JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1964 LP - 1969 DO - 10.2967/jnumed.110.087072 VL - 52 IS - 12 AU - Makoto Ozawa AU - Kayo Takahashi AU - Ko-hei Akazawa AU - Tadayuki Takashima AU - Hiroko Nagata AU - Hisashi Doi AU - Takamitsu Hosoya AU - Yasuhiro Wada AU - Yilong Cui AU - Yosky Kataoka AU - Yasuyoshi Watanabe Y1 - 2011/12/01 UR - http://jnm.snmjournals.org/content/52/12/1964.abstract N2 - 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. ER -