Abstract
Insulin inhibited the ability of activated pertussis toxin to catalyse the ADP-ribosylation of alpha-Gi in isolated plasma membranes in either the absence of added guanine nucleotides or in the presence of GTP. In contrast, when the non-hydrolysable GTP analogue guanylyl-5'-imido-diphosphate (p[NH]ppG) was added to ribosylation mixtures, to inhibit the action of pertussis toxin in catalysing the ADP-ribosylation of alpha-Gi, then the addition of insulin attenuated the action of p[NH]ppG causing an increase in alpha-Gi ribosylation. Pre treatment of intact hepatocytes with insulin had no effect on the subsequent ability of thiol-preactivated pertussis toxin to cause the ADP-ribosylation of alpha Gi using isolated membranes from such cells. The ability of p[NH]ppG to inhibit forskolin-stimulated adenylate cyclase activity was attenuated in the presence of insulin. Insulin did not cause the phosphorylation of alpha-Gi in either intact hepatocytes or in isolated membranes.
Original language | English |
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Pages (from-to) | 251-256 |
Number of pages | 6 |
Journal | Biochemical and Biophysical Research Communications |
Volume | 165 |
Issue number | 1 |
DOIs | |
Publication status | Published - 30 Nov 1989 |
Keywords
- adenosine diphosphate ribose
- adenylate cyclase
- adenylate cyclase toxin
- animals
- cell membrane
- cells, cultured
- forskolin
- GTP-binding proteins
- guanylyl imidodiphosphate
- insulin
- kinetics
- liver
- male
- pertussis toxin
- phosphorylation
- rats
- rats, inbred strains
- virulence factors, bordetella