Regulation of Pituitary Proopiomelanocortin Gene Expression

Abstract

The proopiomelanocortin (POMC) gene encodes the complex precursor to a variety of biologically active, important neuroendocrine peptides. It is expressed in a variety of tissues in the mammal, but its main site of expression is the pituitary anterior lobe corticotroph and, in some species, the intermediate lobe melanotroph. The POMC molecule is posttranslationally processed to different biologically active peptides in these two cell types, with adrenocorticotropic hormone (ACTH), β-lipotrophic hormone (β-LPH), and β-endorphin being major products in the corticotroph and a-melanocyte-stimulating hormone (α-MSH), corticotropin-like intermediate lobe peptide (CLIP), and acetyl-β-endorphin in the melanotroph (Eipper and Mains 1980). This array of different biological activities derived from the POMC molecule possibly necessitates the complex regulation of POMC peptide secretion and POMC gene expression observed in the pituitary. Regulation of POMC peptide secretion has recently been reviewed in several places (Antoni 1986; Jones and Gillham 1988). This review will deal primarily with the regulation of POMC gene expression in rat and mouse pituitary tissues, the species in which the majority of the work has been done although examples of other mammalian systems will be used where appropriate (see also Chaps. 14 and 26).KeywordsAnterior LobeIntermediate LobeAtT20 CellPOMC mRNAPOMC GeneThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.