Glucose-6-phosphate dehydrogenase activity in CaNT tumours of different volume and response to tumour clamping and X-irradiation.
Changes in the levels of glucose-6-phosphate dehydrogenase (G6P-DH) activity, versus tumour volume were measured in vivo under normoxic conditions in the CaNT tumours grown in CBA mice. A monotonically increasing relation was found. Artificially induced tumour hypoxia resulting from 15 min of clamping was accompanied by enhanced G6P-DH activity, but one hour after release of the clamps (reflow), the specific activity of the enzyme decreased to about the same level as that of the normoxic controls. Also the levels of G6P-DH activity in normoxia were measured one hour after 5, 10 and 15 Gy of X-rays (100 kVp). A significantly higher G6P-DH activity which increased with dose, was found in the tumours. This paper gives evidence of increased G6P-DH activity linked with tumour progression, under gradual amplification of the metabolic unbalance. The augmentation of G6P-DH following X-irradiation probably represents a cellular adaptive defence mechanism during the demand for increased metabolism.
Szeinfeld
D
D
Research Institute for Medical Biophysics, SA Medical Research Council, Tygerberg.
D000230:Adenocarcinoma / Q000098:blood supply / Q000201:enzymology* / Q000473:pathology; D000818:Animals; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism* / Q000528:radiation effects; D007511:Ischemia / Q000201:enzymology; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA
D005954:Glucosephosphate Dehydrogenase