Epinephrine: effect on uptake of iodine by dispersed cells of calf thyroid gland.

In isolated thyroid cells I-epinephrine (0.1 and 10.0 micrograms per milliliter), norepinephrine and isoproterenol consistently stimulated the accumulation and organic binding of iodine. The effect was partially inhibited by phentolamine, but not propranolol, and hence may be mediated by alpha receptors. Theophylline did not mimic or enhance the epinephrine effect, suggesting that the latter may not result from activation of adenyl cyclase.