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Coupling of Corticotropin‐Releasing Hormone Receptors to Adenylyl Cyclase in Human Y‐79 Retinoblastoma Cells
Author(s) -
Olianas Maria C.,
Lampis Giorgio,
Onali Pierluigi
Publication year - 1995
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1995.64010394.x
Subject(s) - adenylyl cyclase , cholera toxin , gs alpha subunit , adcy9 , receptor , corticotropin releasing hormone , medicine , vasoactive intestinal peptide , endocrinology , stimulation , g protein , adcy10 , chemistry , biology , neuropeptide
In human Y‐79 retinoblastoma cells, corticotropin‐releasing hormone (CRH) stimulates adenylyl cyclase activity and increases cyclic AMP accumulation. Different CRH analogues mimic the CRH stimulation of adenylyl cyclase and show similar sensitivity to the CRH receptor antagonist α‐helical CRH 9–41 . Vasoactive intestinal peptide (VIP) also increases the enzyme activity but less potently than CRH, and its effect is counteracted by the VIP receptor antagonist [ d ‐ p ‐Cl‐Phe 6 ,Leu 17 ]VIP. The VIP antagonist does not affect the response to CRH. The CRH‐stimulated adenylyl cyclase activity is amplified by Mg 2+ , is inhibited by submicromolar concentrations of Ca 2+ , and requires GTP. Moreover, the CRH stimulation is reduced by pretreatment of cells with cholera toxin and by incubation of membranes with the RM/1 antibody, which recognizes the C‐terminus of the α subunit of G s . In immunoblots, the RM/1 antibody identifies a doublet of 45 and 52 kDa. Two proteins of similar molecular weights are ADP‐ribosylated by cholera toxin. These data demonstrate that in human Y‐79 retinoblastoma cells, specific CRH receptors stimulate cyclic AMP formation by interacting with G s and by affecting a Ca 2+ ‐inhibitable form of adenylyl cyclase.