Effect of vertebrate hormones on the cyclic AMP level in Tetrahymena

Epinephrine, insulin, glucagon and theophylline produced a significant increase in the cAMP level of Tetrahymena, while the enhancing effect of TSH was not significant. The experimental results suggest that Tetrahymena possesses receptors for hormones of higher animals, but has no receptor for the nonsense hormone TSH. The cAMP enhancing effect shown by many hormones of higher animals irrespective of their different functions indicates that apart from the general mediator action of cAMP, some special mediation is also taking place.