DNA-synthesis in irradiated lymphoid cells: effects on temperature on the dose-response curve.

Abstract

SummaryThe effects of x-rays on DNA-synthesis in suspensions of hamster spleen cells was studied. The nature of the dose–response curve was found to be dependent on two factors: the temperature at which the cells were irradiated and the temperature at which they were incubated with tritiated thymidine. Irradiation at 37°c and incubation at 37°c results in a monophasic semilogarithmic dose–response curve with a D37 per cent of 7 krads. Irradiation at 7°c with incubation at 37°c results in a biphasic dose–response relationship with the initial steep part of the curve having a D37 per cent of 4 krads and the shallow part a D37 per cent of 28 krads. 20°c irradiation followed by incubation at 37°c results in a biphasic curve with a steep portion having a D37 per cent of 4 krads and a shallow portion with a D37 per cent of 28 krads. Lowering the irradiation temperature to 7°c and incubating the irradiated cells at 17°c results in a monpohasic response with a D37 per cent of about 20 krads, whereas irradiation a...