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The radiosensitivity of rat thymocytes.
The Biochemical Journal
|September 1, 1986
Summary
Gamma irradiation inhibits superoxide production in rat thymocytes by blocking NADPH oxidase. This radiosensitivity in small lymphocytes is linked to reduced NADPH levels, potentially explaining radiation-induced cell death.
Area of Science:
- Biochemistry
- Cell Biology
- Radiation Biology
Background:
- Plasma membrane-associated NADPH oxidase produces superoxide in thymocytes.
- Ionizing radiation can induce cell death in lymphocytes.
Purpose of the Study:
- To investigate the effect of gamma irradiation on NADPH oxidase activity in rat thymocytes.
- To identify the radiosensitive cell population and the metabolic basis for radiation-induced lymphocyte death.
Main Methods:
- In vitro gamma irradiation of rat thymocytes.
- Differential centrifugation to isolate cell components.
- Biochemical assays to measure NADPH oxidase activity and NADPH levels.
Main Results:
- Gamma irradiation inhibited plasma membrane-associated NADPH oxidase activity.
- Smaller lymphocytes (approx. 6 microns) were identified as the radiosensitive population.
- Irradiation reduced endogenous NADPH levels, mimicking the effect of GSSG with GSSG reductase inhibition.
Conclusions:
- The inhibition of NADPH oxidase and subsequent reduction in NADPH levels by gamma irradiation may be the metabolic basis for interphase death in small lymphocytes.
- The study highlights the role of NADPH oxidase in lymphocyte radiosensitivity.