Relationship of adenosine 3',5'-monophosphate to growth and metabolism of Tetrahymena pyriformis.

The concentration of adenosine 3',5'-monophosphate (cyclic AMP) and the activity of adenylate cyclase were determined for the first time in conjuncation with cyclic 3',5'-nucleotide phosphodiesterase (phosphodiesterase) during the growth cycle of Tetrahymena pyriformis. High levels of cyclic AMP observed during early exponential and late stationary phases were associated with elevated adenylate cyclase and decreased phosphodiesterase activities. Adenylate cyclase and cyclic AMP were decreased and phosphodiesterase was increased in cells grown in glucose-supplemented medium. In contrast to findings in mammalian liver, cyclic AMP was decreased during active gluconeogenesis in Tetrahymena. This suggests a different modulation of carbohydrate metabolism in the two species. The results illustrate that both the content of cyclic AMP and its action as a regulatory agent in Tetrahymena are uniquely suited to the metabolism of this organism.