Catalogo Articoli (Spogli Riviste)
Titolo: Stimulation of intracellular free calcium in GH3 cells by gamma 3-melanocyte-stimulating hormone. Involvement of a novel melanocortin receptor?
Autore: Langouche, L; Roudbaraki, M; Pals, K; Denef, C;
- Catholic Univ Louvain, Sch Med, Lab Cell Pharmacol, B-3000 Louvain, Belgium Catholic Univ Louvain Louvain Belgium B-3000 ol, B-3000 Louvain, Belgium
- Titolo Testata:
pagine: 257 - 266
- THYROTROPIN-RELEASING-HORMONE; IMMATURE RAT PITUITARY; ALPHA-MSH ANALOGS; MOLECULAR-CLONING; GROWTH-HORMONE; GAMMA-MELANOTROPIN; TERMINAL FRAGMENT; IN-VITRO; PROOPIOMELANOCORTIN; PEPTIDES;
- Tipo documento:
- Settore Disciplinare:
- Life Sciences
- Indirizzi per estratti:
- Indirizzo: Denef, C Catholic Univ Louvain, Sch Med, Lab Cell Pharmacol, Campus Gasthuisberg O&N, B-3000 Louvain, Belgium Catholic Univ Louvain Campus Gasthuisberg O&N Louvain Belgium B-3000
- L. Langouche et al., "Stimulation of intracellular free calcium in GH3 cells by gamma 3-melanocyte-stimulating hormone. Involvement of a novel melanocortin receptor?", ENDOCRINOL, 142(1), 2001, pp. 257-266
Abstract The melanocortin (MC) gamma 3MSH is a peptide that can be generated from the N-terminal domain of POMC and is believed to signal through the MC3 receptor. We recently showed that it induces a sustained rise in intracellular free calcium levels ([Ca2+](i)) in a subpopulation of pituitary cells, particularly in the lactosomatotroph lineage. In the present study we report that gamma 3MSH and some analogs increase [Ca2+](i) in the GH- and PRL-secreting GH3 cell. line and evaluate on the basis of pharmacological experimentsand gene expression studies which MC receptor may be involved. A dose as low as 1 pM gamma 3MSH induced an oscillating [Ca2+](i) increasein a significant percentage of GH3 cells. Increasing the dose recruited anincreasing number of responding cells; a maximum was reached at 0.1 nM. gamma SMSH, alpha MSH, and NDP-alpha MSH displayed a similar effect. SHU9119,an MC3 and MC4 receptor antagonist, and an MC5 receptor agonist, did not affect the number of cells showing a [Ca2+](i) rise in response to gamma 3MSH. SHU9119 had also no effect when added alone. MTII, a potent synthetic agonist of the MC3, MC4, and MC5 receptor as well as an N-terminally extendedrecombinant analog of gamma 3MSH showed low potency in increasing [Ca2+](i) in GH3 cells, but high potency in stimulating cAMP accumulation in HEK 293 cells stably transfected with the MC3 receptor. In contrast, a peptide corresponding to the gamma 2MSH sequence of POMC-A of Acipenser transmontanusincreased [Ca2+](i) in GH3 cells, but was about 50 times less potent than gamma2- or gamma 3MSH in stimulating cAMP accumulation in the MC3 receptor expressing HEK 293 cells. By means of RT-PCR performed on a RNA extract from GH3 cells, the messenger RNA of the MC2, MC3, and MC4 receptor was undetectable, but messenger RNA of the MC5 receptor was clearly present. These data suggest that the GH3 cell line does not mediate the effect of gamma 3MSH through the MC3 receptor. The involvement of the MC5 receptor is unlikely, but cannot definitely be excluded. The findings animate the hypothesis that there exists a second, hitherto unidentified, MC receptor that displays high affinity for gamma 3MSH.
ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 21/09/20 alle ore 12:54:32