A new animal model for studies of in vivo folate kinetics

Characterization of transport kinetics involved in tissue folate supply has been limited by the inability to accurately measure the uptake and metabolism of folate by rapidly proliferating tissues. The present report describes a new animal model that uses subcutaneous fibrosarcoma implants as a target tissue for studies of folate supply. The fibrosarcoma grows rapidly as a well-encapsulated, nonmetastasizing nodule(s) and does not disrupt the animal's normal growth and nutrition. Moreover, the tumor nodules avidly take up labeled folate and can be removed easily by local excision for measurements of uptake and intracellular metabolism of folate.