EVALUATION OF SPECIFIC BINDING OF NERVE G ROWTH-FACTOR AND EPIDERMAL GROWTH-FACTOR BY PC12 CELLS IN THE INITIAL PERIOD OF THEIR TRANSDIFFERENTIATION

The level of specific binding of labeled NGF by rat pheochromocytoma P C12 cells does not depend on the degree of their differentiation but i s largely determined by the state of cytoskeletal tubulin structures. Their destruction by colchicine leads to the reduction oi the ligand-r eceptor interaction, and pretreatment with the nerve growth protein co nsiderally limits it. A daylong priming of the cells with NGF signific antly decreases both high- and low-affinity uptake of EGF, setting the m to the differentiation mode that implies inhibition of proliferation in response to a mitogenic factor.