title: The radiosensitivity of rat thymocytes.
abstract: gamma-Irradiation in vitro apparently blocked a plasma-membrane associated, superoxide-producing, NADPH oxidase in rat thymocytes. Differential centrifugation of the mixed thymocytes indicated the smaller lymphocytes (approx. 6 microns diameter) to be the radiosensitive population. The oxidase system co-isolated in part with thymus nuclei and could be solubilized by detergent treatment [Bellavite, Jones, Cross, Papini & Rossi (1984) Biochem. J. 223, 639-648]. Endogenous NADPH was the rate-limiting component for superoxide formation in vitro. The level of NADPH was lowered by gamma-irradiation, an effect mimicked by GSSG in the presence of 50 microM-ZnCl2 to inhibit GSSG reductase. These findings are suggested as the metabolic basis for interphase death of small lymphocytes exposed to ionizing radiation.
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism / Q000528:radiation effects; D005720:Gamma Rays; D005947:Glucose / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism / Q000528:radiation effects; D019255:NADPH Oxidases; D010101:Oxygen Consumption / Q000528:radiation effects; D010427:Pentose Phosphate Pathway / Q000528:radiation effects; D051381:Rats; D011919:Rats, Inbred Strains; D013481:Superoxides / Q000378:metabolism / Q000528:radiation effects; D013950:Thymus Gland / Q000166:cytology / Q000528:radiation effects*
chemical_list: D013481:Superoxides; D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases; D005947:Glucose