Fig. 4

GPCR dependent production of intracellular cAMP determines secretory function in specialized cells of different exocrine organs. Among GPCRs determinant for the differentiation and function of tissues displaying the gsp+ phenotype, are secretin family receptors (glucagon, GIP, secretin, VIP, GHRH) and LGR receptors (LGR 1-8). The same pathways instrumental to zonation and differentiation are also likely acting on transcriptional programs related to the differentiation stage reached by the cells. NR5A master regulators are present in cells displaying the gsp+ phenotype (thyroid [95], osteoblast [93], somatotropic, pancreatic cells [98], hepatocytes, intestinal crypt [91], adrenocortical, Leydig and granulosa cells [99])