cGMP phosphodiesterase activity in diabetic rats eyes in normoxic, hypoxic and hyperoxic conditions

Phosphodiesterase activity was tested on homogenized eyes of pre-diabetic rats kept in normoxic, hypoxic and hyperoxic conditions, with the aim of correlating any difference in PDE activity with variations in atmospheric oxygen contents. The activity of the cGMP phosphodiesterase (cGMP-PDE) was tested. Phosphodiesterases seem to be particularly susceptible to variations in oxygen tension, suggesting an important role of cyclic nucleotides in cellular adaptive processes. cGMP-PDE activity increases lightly in normoxic, hypoxic and hyperoxic conditions in pre-diabetic rats. The second messenger, cGMP, plays important roles in mediating the biological effects of a wide variety of first messengers. In particular, cGMP in the eye is an important mediator for the mechanism of sight. The intracellular levels of cyclic nucleotides depend upon the rates of synthesis and degradation, actuated, respectively, by cyclases and phosphodiesterases (PDEs). Therefore, PDEs seem to play an important role in a wide variety of physiological processes.