Control of thyroid cell proliferation: The example of the dog thyrocyte

The thyroid cell is controlled by a variety of extracellular signal molecules, each interacting through specific receptors with a few intracellular signalling cascades. The main physiological control is exerted in all species by pituitary thyrotropin. Depending on the species, this regulation is complemented or modulated by a variety of hormones, neurotransmitters and local hormones. The main aspects of thyroid cell biology are controlled: the level of its function, the expression of its differentiation and growth and proliferation. In this short review we shall outline our knowledge about the first two aspects but mainly concentrate on the latter, using out own work on the dog thyroid as a framework.