title: Diadenosine polyphosphates and the control of cyclic AMP concentrations in isolated rat liver cells.
abstract: Extracellular diadenosine polyphosphates (Ap(n)A), through their interactions with appropriate P(2) receptors, influence a diverse range of intracellular activities. In particular, Ap(4)A stimulates alterations in intracellular calcium homeostasis and subsequent activation of glycogen breakdown in isolated liver cells. Here we show that, like ATP, Ap(4)A and other naturally occurring diadenosine polyphosphates attenuate glucagon-stimulated accumulation of cyclic AMP in isolated rat liver cells. The characteristics of Ap(4)A- and ATP-dependent modulation of glucagon-stimulated cyclic AMP accumulation are similar. These results are discussed in the context of the repertoire of intracellular signalling processes modulated by extracellular nucleotides.
authors.affiliation: School of Biological Sciences, University of Liverpool, Liverpool, UK.
authors.forename: M
authors.initials: M
authors.lastname: Edgecombe
authors.forename: A G
authors.initials: AG
authors.lastname: McLennan
authors.forename: M J
authors.initials: MJ
authors.lastname: Fisher
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism*; D015226:Dinucleoside Phosphates / Q000378:metabolism* / Q000494:pharmacology; D005934:Glucagon / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D018048:Receptors, Purinergic P2 / Q000378:metabolism; D015398:Signal Transduction; D013873:Thionucleotides / Q000494:pharmacology
chemical_list: D015226:Dinucleoside Phosphates; D018048:Receptors, Purinergic P2; D013873:Thionucleotides; C012275:P(1),P(5)-di(adenosine-5'-)pentaphosphate; C020733:diadenosine tetraphosphate; C070070:diadenosine 5',5''''-P1,P6-hexaphosphate; D000255:Adenosine Triphosphate; D005934:Glucagon; D000242:Cyclic AMP; C008501:2-methylthio-ATP