Rgs16 mRNA is expressed in periportal hepatocytes. In situ hybridization (dark field) of (A-C) Rgs16 and (D) PEPCK mRNA expression in liver. ( A-B ) Rgs16 mRNA is expressed specifically in periportal hepatocytes of mice fasted from ZT4 and sacrificed at ZT16 (12 hr L:D). ( C ) Rgs16 was not expressed in liver of fed mice. ( D ) PEPCK mRNA expression was observed in hepatocytes throughout the liver of fasted mice (ZT4-ZT16; same liver as 3A, neighbouring section), although most abundantly in periportal hepatocytes. ZT, Zeitgeber Time. Scale bar = 100 μm.