AN UPTAKE SYSTEM FOR DIETARY ALKALOIDS IN POISON FROGS (DENDROBATIDAE)

The skin of poison frogs (Dendrobatidae) contains a wide variety of al kaloids that presumably serve a defensive role. These alkaloids persis t for years in captivity, but are not present in captive-raised frogs. Alkaloids fed to poison frogs (Dendrobates, Phyllobates, Epipedobates ) are readily accumulated into skin, where they remain for months. The process can be selective; an ant indolizidine is accumulated, while a n ant pyrrolidine is not. Frogs (Colostethus) of the same family, whic h do not normally contain alkaloids, do not accumulate alkaloids. Such an alkaloid uptake system provides a means of maintaining skin alkalo ids and suggests that some if not all such 'dendrobatid alkaloids' may have a dietary origin.