Regulation of proopiomelanocortin (POMC) mRNA levels in primary pituitary cultures.
The effect of a variety of neurotransmitters and of corticotropin releasing factor (CRF) upon levels of mRNA coding for proopiomelanocortin (POMC) was studied in primary cultures of rat pituitary. Total nucleic acid was extracted from cells, fixed on nitrocellulose and hybridized to a single-stranded alpha 32P-labeled DNA complementary to 150 bases of mouse POMC mRNA. After two days incubation with CRF (10(-8) M), the levels of POMC mRNA in both the anterior (AL) and the intermediate lobe (IL) cells increased by about 100%. A similar increase in the IL cells was seen after incubation with the beta-adrenergic agonist isoprenalin (10(-6) M). In contrast, dopamine (10(-6) M) and GABA (10(-6) M) decreased POMC mRNA levels in the IL cells to about 50% of control levels without affecting POMC mRNA levels in the AL cells. In both pituitary lobes, POMC mRNA was decreased by the Ca2+-channel blocker D600 (10(-5) M) and increased by forskolin (10(-6) M). This indicates that both cAMP and Ca2+ ions play an important role as intracellular messengers for the control of POMC gene expression in normal melanotrope and corticotrope cells.
D000818:Animals; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D005796:Genes; D008297:Male; D010902:Pituitary Gland / Q000378:metabolism*; D010903:Pituitary Gland, Anterior / Q000378:metabolism; D011333:Pro-Opiomelanocortin / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D011919:Rats, Inbred Strains
D012333:RNA, Messenger; D011333:Pro-Opiomelanocortin