Cell kinetics in the epidermis of the toad Bufo bufo bufo (L.) after partial hypophysectomy followed by corticotrophin treatment (an autoradiographic study).

1. Cell kinetic parameters in the epidermis of partially hypophysectomized, ACTH-treated toads whose moulting frequency was increased threefold were studied using labelled thymidine and the autoradiographic technique. 2. The labelling index, length of S-phase and cycle time of stratum germinativum cells changed slowly as a function of the number of ACTH injections, and so did the migration of cells from stratum germinativum to stratum corneum. 3. A cell production in stratum germinativum of normal toads in excess of cell loss, as demonstrated by Levi & Nielsen (1982) should make it possible to maintain a status quo over a limited period of time following ablation of pars distalis and ACTH treatment.