Gene expression of adenylate cyclase (AC) and phosphodiesterase (PDE) isoforms in bovine trabecular meshwork cells. The different AC (1–9) and cAMP-specific PDE isoforms (PDE3, 4, 5, and 8) were studied using total RNA and sequence-specific oligonucleotide primers. (A) Expression of AC isoforms 3, 4, 6, and 7 in bovine TM cells. (B) Expression of PDE4A, 4B, and 4D of the PDE4 family and PDE5 and 8. Expression of the other isoforms of ACs and PDEs was undetectable.