LAUSR

OBJECTIVES Phosphodiesterases comprise a superfamily of enzymes that hydrolyze and inactivate cyclic AMP (cAMP) and/or cyclic GMP (cGMP), thereby regulating cellular signaling mechanisms. We herein investigated the production of phosphodiesterase 2A (PDE2A) in the mouse submandibular gland. DESIGN The expression and localization of the mRNA and protein of PDE2A were examined in the submandibular gland of male and female mice using the reverse transcription-polymerase chain reaction, in situ hybridization, Western blotting, and immunohistochemistry. RESULTS Among the different species of phosphodiesterases examined in the mouse submandibular gland, PDE2A, which hydrolyzes cAMP and cGMP, exhibited a marked sexual difference; it was more abundantly expressed in females. The mRNA and protein signals for PDE2A were intense in all acinar and duct portions, including the striated duct, in females, whereas in males, these signals were markedly weaker in the granular convoluted duct, the counterpart of the female striated duct, than in acini and other duct portions. Furthermore, the signals for protein kinases A and G1, which are intracellular effectors of cAMP and cGMP, respectively, were markedly weaker in the male granular convoluted duct. CONCLUSIONS These results suggest that cyclic nucleotide-dependent signaling mechanisms function poorly in granular convoluted duct cells in the mouse submandibular gland.