Distinct Guanine Nucleotide Binding Protein Alpha-Subunit Receptor Coupling in GH Cell Lines: Effects of Bromocriptine and Hormones on Effector Enzyme Modulation

2001 ◽  
Vol 11 (6) ◽  
pp. 339-352 ◽  
Author(s):  
Per Johansen ◽  
Ruth Paulssen ◽  
Trine Bjøro ◽  
Kaare Gautvik ◽  
Jan Gordeladze
Keyword(s):  
Cell Lines ◽  
Binding Protein ◽  
Nucleotide Binding ◽  
Alpha Subunit ◽  
Guanine Nucleotide ◽  
Guanine Nucleotide Binding Protein ◽  
Receptor Coupling ◽  
Enzyme Modulation ◽  
Guanine Nucleotide Binding ◽  
Protein Alpha Subunit

scholarly journals Chemically induced hypothyroidism produces elevated amounts of the α subunit of the inhibitory guanine nucleotide binding protein (Gi) and the β subunit common to all G-proteins

1987 ◽  
Vol 247 (1) ◽  
pp. 223-227 ◽  
Author(s):  
G Milligan ◽  
A M Spiegel ◽  
C G Unson ◽  
E D Saggerson
Keyword(s):  
Membrane Protein ◽  
G Proteins ◽  
Plasma Membranes ◽  
Binding Protein ◽  
Nucleotide Binding ◽  
Alpha Subunit ◽  
Guanine Nucleotide ◽  
Guanine Nucleotide Binding Protein ◽  
Guanine Nucleotide Binding ◽  
Nucleotide Binding Protein

Adipocytes of hypothyroid rats display an increased responsiveness to agents which function by inhibiting the production of cyclic AMP. Anti-peptide antisera which selectively recognise the alpha subunit of the inhibitory guanine nucleotide binding protein (Gi) detected a 40 kDa polypeptide in adipocyte plasma membranes of both euthyroid and hypothyroid rats. Amounts of the alpha subunit of Gi were elevated some 2-fold in the hypothyroid preparations in comparison with the euthyroid controls, when equal amounts of membrane protein of the two treatments were examined. As cells from the hypothyroid animals contained 2.7 times as much membrane protein as those from the control animals, the amounts of alpha subunit of Gi are elevated some 5.6-fold per cell in adipocytes of the hypothyroid animals compared with the euthyroid controls. Amounts of the 36 kDa beta subunit of G-proteins were also elevated in plasma membranes of adipocytes of hypothyroid animals, in this case by some 50% when compared on a protein basis. These results provide direct evidence for alterations in the amounts of the subunits of Gi caused by the hypothyroid state.

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