Expression of cyclic nucleotide phosphodiesterase 3A in isolated rat submandibular acini

Phosphodiesterase (PDE) 3 has been characterized in isolated rat submandibular acini. PDE3 activity was detected in homogenates of isolated rat submandibular acini; little or no PDE3 activity was found in ducts. About 62% of PDE3 activity in the acini was recovered in the supernatant fractions; 38% in particulate fractions. In the acini, but not ducts, PDE3A mRNA was detected by reverse transcriptase-polymerase chain reaction (RT-PCR). The PDE3-specific inhibitor, cilostamide, increased the ratio of apomucin mRNA/18s rRNA, as quantified by real-time RT-PCR. Our results indicate that PDE3A may be important in regulating cAMP pools that control acini functions.