Identification of functional somatostatin receptors and G-proteins in a new line of human foetal lung fibroblasts.
A new line (FP) of human foetal lung fibroblasts was analysed for the expression of functional, G-protein coupled somatostatin receptors (SSTR). By means of RT-PCR, we identified the expression of SSTR1, SSTR2, SSTR3 and SSTR4, but not SSTR5, subtypes. The same technical approach evidenced the expression of stimulatory (alphas) and inhibitory (alphai1, alphai2 and alphai3) G-protein subunits. The functionality of SSTR was established from the observation of a dose-dependent inhibitory role of SST upon isoproterenol-stimulated adenylyl cyclase activity, an effect that involves G-protein action. Moreover, the functionality of G-proteins was assessed by means of experiments with forskolin and a nonhydrolysable GTP analogue that showed either Gi or Gs activation in the regulation of adenylyl cyclase. Present results represent a first pharmacological characterization of this new line of human foetal lung fibroblasts. The selective presence of some SSTR subtypes and G-protein subunits in addition to the regulatory network of the adenylyl cyclase pathway are features of recognized involvement in cell growth mechanisms. It is of interest for a cell class widely used to study this topic but also important in lung physiology and pathophysiology.
Busto
R
R
Department of Biochemistry and Molecular Biology, University of Alcalá, Alcalá de Henares, Spain.
Carrero
I
I
Zapata
P
P
Colás
B
B
Prieto
J C
JC
D000262:Adenylyl Cyclases / Q000378:metabolism; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D018076:DNA, Complementary / Q000032:analysis; D004622:Embryo, Mammalian; D005347:Fibroblasts / Q000737:chemistry*; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000502:physiology; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000502:physiology; D019204:GTP-Binding Proteins / Q000032:analysis*; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D008168:Lung; D017481:Receptors, Somatostatin / Q000032:analysis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D018076:DNA, Complementary; D017481:Receptors, Somatostatin; D005576:Colforsin; D006165:Guanylyl Imidodiphosphate; D019204:GTP-Binding Proteins; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D019205:GTP-Binding Protein alpha Subunits, Gs; D000262:Adenylyl Cyclases; D007545:Isoproterenol