Alterations in hepatic kinase activity following whole body gamma-irradiation of mice.
The chronological activation of the signaling molecules following whole body gamma-irradiation was investigated in mouse liver. The activity of two kinases, tyrosine kinase and protein kinase C (PKC), was found to respond differently to gamma-irradiation. Tyrosine kinase was found to respond to much lower doses of irradiation (10 cGy), whereas PKC was found to be activated at comparatively higher doses (3 Gy). Tyrosine kinase showed a sharp activation at 30 min and then a decline to normal values at 1 h. Activation of PKC was apparent at as early as 15 min of irradiation and showed a maximal increase at 30 min. This was followed by a decline to normal values at 1 h. The response of the whole organ was found to be different from that of reported effects on a single cell. These results suggest that the data obtained from the single-cell studies would have limited application in the experiments involving the whole animal. Interruption of these signals at various steps is currently being used to manipulate tumor response to radiotherapy. In such cases, the difference in response of a single cell and a whole animal must be considered.
Varadkar
P
P
Radiation Biology Division, Bhabha Atomic Research Centre, Maharashtra, India.
Krishna
M
M
Verma
N C
NC
D000818:Animals; D002467:Cell Nucleus / Q000201:enzymology; D003600:Cytosol / Q000201:enzymology; D004307:Dose-Response Relationship, Radiation; D004789:Enzyme Activation; D005720:Gamma Rays; D007425:Intracellular Membranes / Q000201:enzymology; D007700:Kinetics; D008099:Liver / Q000201:enzymology* / Q000528:radiation effects*; D008297:Male; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D015398:Signal Transduction; D014916:Whole-Body Irradiation
D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases