Cyclic AMP levels in migrating and non-migrating newt epidermal cells.

Cyclic AMP (cAMP) levels were measured in 8-hour migrating wound epithelial and non-migrating epithelial cells of the newt. Tissues were collected in vivo and in vitro with and without epidermal-dermal separation by collagenase. Regardless of manner of collection and treatment, cAMP levels were always significantly higher in the migrating cells. Levels were also measured in 28-hour and 36-hour wound epithelia. There was a progressive decline in levels in wound epithelia between 8, 28, and 36 hours, suggesting that levels were in the process of returning to normal. When cells were treated with a dose of cAMP and theo-phylline previously shown to inhibit migration, levels of cAMP were much higher than any migrating epithelium. The fact that cAMP inhibits migration, yet migrating cells have higher cAMP levels, seems contradictory at first, but possible explanations are advanced to account for the apparent discrepancy.