Journal of Endocrinology

Time line. Figure depicts the principal discoveries that contributed to the actual understanding of TRH neurons and regulation of the hypothalamus–pituitary–thyroid axis (HPT). Above the blue line are marked some of the main findings in techniques or in cellular biology. Below are those related to the HPT axis. Space constraints makes it impossible to cite each piece of work, and some examples represent the ideas and paradigms of various authors. BMR, basal metabolic rate; IEGs, immediate early genes; ISH, in situ hybridization; KO, knock out; ME, median eminence; NGF, nerve growth factor; POMC, proopiomelanocortin; PVN, paraventricular nucleus; TH, thyroid hormones; TRF, thyrotropin-releasing factor.