Idioma:

Inactivation of pertussis toxin-sensitive guanyl nucleotide-binding proteins increase parathyroid hormone receptors and reverse agonist-induced receptor down-regulation in ROS 17/2.8 cells

ABDUL-BADI ABOU-SAMRA ; JUEPPNER, H ; POTTS, J. T. JR ; SEGRE, G. V

Endocrinology (Philadelphia), 1989-11, Vol.125 (5), p.2594-2599 [Periódico revisado por pares]

Bethesda, MD: Endocrine Society

Sem texto completo

Citações Citado por

Enviar para

Título:
Inactivation of pertussis toxin-sensitive guanyl nucleotide-binding proteins increase parathyroid hormone receptors and reverse agonist-induced receptor down-regulation in ROS 17/2.8 cells
Autor: ABDUL-BADI ABOU-SAMRA ; JUEPPNER, H ; POTTS, J. T. JR ; SEGRE, G. V
Assuntos: 1-Methyl-3-isobutylxanthine - pharmacology ; 8-Bromo Cyclic Adenosine Monophosphate - pharmacology ; Adenylate Cyclase Toxin ; Animals ; Biological and medical sciences ; Cell Line ; Cholera Toxin - pharmacology ; Clone Cells ; Colforsin - pharmacology ; Cyclic AMP - metabolism ; Down-Regulation - drug effects ; Fundamental and applied biological sciences. Psychology ; GTP-Binding Proteins - antagonists & inhibitors ; Hormones. Regulation ; Kinetics ; Osteosarcoma ; Parathyroid Hormone - pharmacology ; Parathyroid Hormone - physiology ; Peptide Fragments - pharmacology ; Pertussis Toxin ; Rats ; Receptors, Cell Surface - physiology ; Receptors, Parathyroid Hormone ; Teriparatide - analogs & derivatives ; Theophylline - analogs & derivatives ; Thyroid. Parathyroid. Ultimobranchial body ; Vertebrates: endocrinology ; Virulence Factors, Bordetella - pharmacology
É parte de: Endocrinology (Philadelphia), 1989-11, Vol.125 (5), p.2594-2599
Notas: ObjectType-Article-2
SourceType-Scholarly Journals-1
ObjectType-Feature-1
content type line 23
Descrição: We examined mechanisms of down-regulation of PTH receptors and desensitization of the PTH-stimulated increase in intracellular cAMP in clonal rat osteosarcoma cells, ROS 17/2.8. ROS cells treated with 10 nM [Nle8,Nle18,Tyr34] bovine (b) PTH-(1-34) amide (NlePTH) for 3 days showed loss of specific PTH binding and PTH-stimulated cAMP accumulation to 10% of that in vehicle-treated control cells. Treatment of these cells with both 0.5 mM 8-bromo-cAMP (8-Br-cAMP) and 1 mM methylisobutylxanthine or 100 ng/ml cholera toxin for 3 days elicited no change in either of these responses. Treatment with 10 nM NlePTH for 3 days did not modify the cAMP accumulation stimulated by 30 microM forskolin or 1 micrograms/ml cholera toxin, indicating that agonist-specific desensitization of PTH-stimulated cAMP accumulation is not due to diminished activity of either the stimulatory guanyl nucleotide regulatory subunit (Gs) or the catalytic subunit of the adenylate cyclase. Treatment of ROS cells with pertussis toxin (PT; 10 ng/ml) for 12, 24, 48, and 72 h increased specific PTH binding by 21%, 28%, 35%, and 39%. The increase in PTH binding was associated with a parallel increase in PTH-stimulated cAMP accumulation and was due to an increase in the number of PTH receptors. PTH receptor affinity remained constant (apparent Kd = 0.3 nM). PT treatment of the cells partially blocked agonist-specific PTH receptor down-regulation. PT catalyzed ADP ribosylation of 41K and 39K membrane proteins, consistent with the alpha-subunits of Gi and Go, respectively. In conclusion, agonist-induced PTH receptor down-regulation in ROS 17/2.8 cells is cAMP independent and can be reversed by PT treatment. PTH receptor expression in these cells appears to be under tonic inhibitory control by mechanisms involving a PT-sensitive G protein(s).
Editor: Bethesda, MD: Endocrine Society
Idioma: Inglês

Links

Voltar para lista de resultados

Realização: Logos de Redes Sociais:

Inactivation of pertussis toxin-sensitive guanyl nucleotide-binding proteins increase parathyroid hormone receptors and reverse agonist-induced receptor down-regulation in ROS 17/2.8 cells

ABDUL-BADI ABOU-SAMRA ; JUEPPNER, H ; POTTS, J. T. JR ; SEGRE, G. V

Bethesda, MD: Endocrine Society

Buscando em bases de dados remotas. Favor aguardar.