Weight Changes and Water Consumption of Rats Exposed to Whole-Body X-Irradiation

Abstract

The wt. loss of a fasting rat of 180-380 g. is independent of the initial wt. and is unaffected by 500 r whole-body X-irradiation. This implies that X-irradiation does not greatly alter the overall metabolism or the degree of hydration of tissues of the fasting animal. Fed irradiated rats lose wt. for a period of time which is proportional to the dose received. If the dose is sublethal they then grow at a rate parallel to that of control animals. The time required to regain the wt. of the day of irradiation in 200 g. rats is a linear function of the dose up to 600 r. This index is reproducible enough to detect increments of 50 r in dosage from the avg. wt. changes in a group of 5 rats. Fed irradiated rats show 2 periods of polydipsia. The 1st period occurs within 24 hrs. after exposure. The 2d period occuring some 48 hrs. or later is associated with recovery and the resumption of normal food intake and growth of the exposed animals.