Schematic cascade of transcription factors and signalling molecules highlighting some of the known genes and their expression domains. ACTH, adrenocorticotropic hormone; E, embryonic day; FSH, follicle-stimulating hormone; GH, growth hormone; LH, luteinizing hormone; MSH, melanocyte stimulating hormone; POMC, proopiomelanocortin; PrL, prolactin; RP,; TSH, thyroid stimulating hormone. Adapted from Kelberman D et al. Genetic regulation of pituitary gland development in human and mouse. End Reviews 2009; 30(7): 790–829, with permission.