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Titolo:
COMPARISON OF THE FORMS OF THE DOPAMINE D-2 RECEPTOR EXPRESSED IN GH(4)C(1) CELLS
Autore:
BURRIS TP; FREEMAN ME;
Indirizzi:
FLORIDA STATE UNIV,DEPT BIOL SCI,BIOMED RES FACIL,B-221 TALLAHASSEE FL 32306 FLORIDA STATE UNIV,DEPT BIOL SCI,BIOMED RES FACIL TALLAHASSEE FL 32306 FLORIDA STATE UNIV,INST MOLEC BIOPHYS TALLAHASSEE FL 32306
Titolo Testata:
Proceedings of the Society for Experimental Biology and Medicine
fascicolo: 3, volume: 205, anno: 1994,
pagine: 226 - 235
SICI:
0037-9727(1994)205:3<226:COTFOT>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
ANTERIOR-PITUITARY-CELLS; THYROTROPIN-RELEASING-HORMONE; RAT LACTOTROPH CELLS; INOSITOL PHOSPHATE PRODUCTION; PROLACTIN SECRETION; MOLECULAR-BIOLOGY; ADENYLYL CYCLASE; PRIMARY CULTURES; INHIBITION; CALCIUM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
43
Recensione:
Indirizzi per estratti:
Citazione:
T.P. Burris e M.E. Freeman, "COMPARISON OF THE FORMS OF THE DOPAMINE D-2 RECEPTOR EXPRESSED IN GH(4)C(1) CELLS", Proceedings of the Society for Experimental Biology and Medicine, 205(3), 1994, pp. 226-235

Abstract

The effects of dopamine (DA) on prolactin (PRL) secretion, phosphoinositide metabolism, cytosolic calcium concentrations ([Ca2+](i)), and cAMP production in GH(4)C(1) cells expressed either the short (GH(4)ZR(7) cells) or long (GH(4)I(12) cells) form of the rat DA D-2 receptor were compared in this study. The GH(4)C(1) cell line is derived from the rat anterior pituitary gland and lacks functional DA receptors. The GH(4)ZR(7) and GH(4)I(12) cell lines have been transfected with eitherthe short or the long form of the D-2 receptor, respectively. In thisstudy, the functional coupling of these receptors to both basal and stimulated PRL secretion and to common second messenger systems was examined. Both cell types expressing DA receptors exhibited similar saturable binding to the D-2 antagonist [H-3]spiperone (K-d GH(4)ZR(7) = 96+/- 8 pM, K-d GH(4)I(12) = 107 +/- 49 pM). In GH(4)ZR(7) cells, 1 and10 mu M DA inhibited basal PRL secretion by 37% and 58%, respectively. In GH(4)I(12) cells, 1 and 10 mu M DA inhibited basal PRL secretion by 63% and 54%, respectively. In GH(4)ZR(7) cells, 10 mu M DA completely reversed the stimulatory effects of 1-100 nM thyrotropin-releasing hormone (TRH), and 1 mu M DA attenuated the stimulatory effects of 10 and 100 nM TRH. Interestingly, GH(4)I(12) cells were not responsive toTRH. In both cell lines, the inhibitory effects of DA were blocked bythe specific D-2 antagonist, eticlopride. The stimulatory effects of TRH on [Ca2+](i) were dose dependent and could be blocked (at least inGH(4)ZR(7) cells) by prior treatment of the cells with 1 mu M DA. Theability of dopamine to block the TRH-mediated increase in [Ca2+](i) was attenuated by eticlopride. DA (1 mu M) had no effect on resting [Ca2+](i) in either cell line expressing DA receptor. TRH (100 nM) maximally stimulated total inositol phosphate (IP) accumulation to values approximately three times greater than controls in GH(4)C(1) and GH(4)ZR(7) cells only. DA had no effect on basal or TRH-stimulated IP accumulation in any of the cell lines. DA (1 and 10 mu M) inhibited cAMP production by 40% and 39%, respectively, in GH(4)ZR(7) cells. Similarly, in GH(4)I(12) cells, DA (1 and 10 mu M) inhibited cAMP production by 48% and 60%, respectively. These data indicate that both the long and short forms of the D-2 receptors play similar roles when expressed in GH(4)C(1) cells. However, maximal inhibition of PRL in these cell lines is approximately 20% less than that of normal lactotrophs.

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Documento generato il 27/01/20 alle ore 13:56:31