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Article: Decreased potency of glucoagon on transformed-induced MDCK cells does not reflect an alteration of adenylate cyclase components

TitleDecreased potency of glucoagon on transformed-induced MDCK cells does not reflect an alteration of adenylate cyclase components
Authors
Issue Date1987
PublisherThe Endocrine Society. The Journal's web site is located at http://endo.endojournals.org
Citation
Endocrinology, 1987, v. 121 n. 4, p. 1438-1446 How to Cite?
AbstractThe selective loss of glucagon sensitivity of transformed MDCK cells can be restored by differentiation inducers, a process which requires RNA and protein synthesis and glycosylation. Although the glucagon dose-response curve of normal MDCK cells resembled that of liver and kidney (K(act) = 10 nM), the transformed-induced cells were 10-fold less sensitive to the hormone [activation constant (K(act)) = 100 nM]. Additionally, the stimulation of cAMP synthesis by a glucagon fragment (glucagon 1-27) in transformed-induced cells was greatly reduced compared to normal cells. The adenylate cyclase regulatory components of transformed-induced MDCK cell membranes seemed unaltered compared to the parental line. both contained equivalent amounts of cholera and pertussis toxin substrates, and soluble extracts were equally capable of reconstituting isoproterenol responsiveness of S49 cyc - membranes. However, membrane fusion studies demonstrated that the glucagon sensitivity of transformed-induced membranes could not be reconstituted with heterologous membranes. When donor transformed-induced membranes (with inactivated adenylate cyclase) were fused with acceptor HeLa membranes (normally unresponsive to glucoagon and prostaglandin E), such hybrids were unresponsive to glucagon, although responsiveness to prostaglandin E was evident. Parallel hybrids with normal MDCK membranes were responsive to both glucagon and prostaglandin E. This difference could not be explained by an inhibitory effect of transformed-induced membranes on receptor-adenylate cyclase coupling under the fusion conditions: the ability of these membranes to serve as an acceptor for the reconstitution of vasoactive intestinal peptide responsiveness was identical to that of normal MDCK cells. The data suggest that the glucagon sensitivity induced in transformed MDCK cells differs significantly from that of the parental line. However, these differences cannot be explained by alterations of transformed-induced membrane components relevant to the coupling of hormone receptors to adenylate cyclase.
Persistent Identifierhttp://hdl.handle.net/10722/167472
ISSN
2015 Impact Factor: 4.159
2015 SCImago Journal Rankings: 2.363
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorBeckner, SKen_US
dc.contributor.authorWright, DEen_US
dc.contributor.authorLin, MCen_US
dc.date.accessioned2012-10-08T03:07:27Z-
dc.date.available2012-10-08T03:07:27Z-
dc.date.issued1987en_US
dc.identifier.citationEndocrinology, 1987, v. 121 n. 4, p. 1438-1446en_US
dc.identifier.issn0013-7227en_US
dc.identifier.urihttp://hdl.handle.net/10722/167472-
dc.description.abstractThe selective loss of glucagon sensitivity of transformed MDCK cells can be restored by differentiation inducers, a process which requires RNA and protein synthesis and glycosylation. Although the glucagon dose-response curve of normal MDCK cells resembled that of liver and kidney (K(act) = 10 nM), the transformed-induced cells were 10-fold less sensitive to the hormone [activation constant (K(act)) = 100 nM]. Additionally, the stimulation of cAMP synthesis by a glucagon fragment (glucagon 1-27) in transformed-induced cells was greatly reduced compared to normal cells. The adenylate cyclase regulatory components of transformed-induced MDCK cell membranes seemed unaltered compared to the parental line. both contained equivalent amounts of cholera and pertussis toxin substrates, and soluble extracts were equally capable of reconstituting isoproterenol responsiveness of S49 cyc - membranes. However, membrane fusion studies demonstrated that the glucagon sensitivity of transformed-induced membranes could not be reconstituted with heterologous membranes. When donor transformed-induced membranes (with inactivated adenylate cyclase) were fused with acceptor HeLa membranes (normally unresponsive to glucoagon and prostaglandin E), such hybrids were unresponsive to glucagon, although responsiveness to prostaglandin E was evident. Parallel hybrids with normal MDCK membranes were responsive to both glucagon and prostaglandin E. This difference could not be explained by an inhibitory effect of transformed-induced membranes on receptor-adenylate cyclase coupling under the fusion conditions: the ability of these membranes to serve as an acceptor for the reconstitution of vasoactive intestinal peptide responsiveness was identical to that of normal MDCK cells. The data suggest that the glucagon sensitivity induced in transformed MDCK cells differs significantly from that of the parental line. However, these differences cannot be explained by alterations of transformed-induced membrane components relevant to the coupling of hormone receptors to adenylate cyclase.en_US
dc.languageengen_US
dc.publisherThe Endocrine Society. The Journal's web site is located at http://endo.endojournals.orgen_US
dc.relation.ispartofEndocrinologyen_US
dc.titleDecreased potency of glucoagon on transformed-induced MDCK cells does not reflect an alteration of adenylate cyclase componentsen_US
dc.typeArticleen_US
dc.identifier.emailLin, MC:mcllin@hkucc.hku.hken_US
dc.identifier.authorityLin, MC=rp00746en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1210/endo-121-4-1438-
dc.identifier.pmid3653036-
dc.identifier.scopuseid_2-s2.0-0023162431en_US
dc.identifier.volume121en_US
dc.identifier.issue4en_US
dc.identifier.spage1438en_US
dc.identifier.epage1446en_US
dc.identifier.isiWOS:A1987K317100032-
dc.publisher.placeUnited Statesen_US
dc.identifier.scopusauthoridBeckner, SK=7004064238en_US
dc.identifier.scopusauthoridWright, DE=7404381610en_US
dc.identifier.scopusauthoridLin, MC=7404816359en_US

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