DISSOCIATION OF THE STIMULI FOR CELL HYPERTROPHY AND CELL-DIVISION INTHE DOG THYROCYTE - INSULIN PROMOTES PROTEIN ACCUMULATION WHILE TSH TRIGGERS DNA-SYNTHESIS

Thyrotropin through the cyclic AMP cascade, and in the presence of ins ulin or IGF-1, activates the proliferation of dog thyroid cells, In th is work it is shown that insulin, presumably acting through the IGF-1 receptors, stimulates the accumulation of protein and increases cell m ass but does not induce DNA synthesis, TSH, on the contrary, induces D NA synthesis, in the presence of insulin, but not protein accumulation , It is proposed that insulin induces the increase of cell mass that i s a prerequisite for the mitogenic effect of TSH. (C) 1995 Academic Pr ess, Inc.