Thyroid Hormone Signaling Pathways: Time for a More Precise Nomenclature.

Current literature makes a distinction between two pathways for thyroid hormone signaling: genomic and nongenomic. However, this classification is a source of confusion. We propose a clarification in the nomenclature that may help to avoid unproductive controversies and favor progress in this field of research. Four types of thyroid hormone signaling are defined, and the experimental criteria for classification are discussed.