Table 4. Cyclic nucleotide levels in Y79 cells

Cyclic GMP levels were measured to determine if cGMP analog supplementation to the Y79 cells may lead to increased PDE6 expression. cGMP is known to be important for binding to the non-catalytic sites in rod PDE6 and we reasoned that it may be required for stable expression of the enzyme. Cyclic AMP and cGMP levels were measured in Y79 cells. The cAMP measurement in the current study served as an internal control validating the technique used. The present two cAMP measurements were close to the values previously reported, validating the methods. In prior studies [41] cAMP levels were measured 7 days (*) and 15 days (**) after passage.

                      cGMP (pmols/mg protein)    cAMP (pmols/mg protein)
-------------------   -----------------------   -------------------------
Results this report    0.0519±0.00766 (n=13)    3.31±0.51 (n=2)
Prior results [41]     Not determined           5.5 ±0.91* and 4.7±0.52**