Abstract
In an experiment in which the effect of pituitary removal on the rate of growth of Walker tumor No. 256 was compared with the effect of caloric restriction in intact tumor-bearing male rats, samples of liver, muscle, and tumor tissue were secured for glycogen determinations.
All animals had been fed by stomach tube with a formula composed of
The hypophysectomized animals received twice daily throughout the experiment 1 cc. of this mixture per 40 gm. of body weight, calculated at the beginning of the experiment when tumor weight was negligible. The amount of food received by the controls was varied to maintain the total weight (somatic weight plus tumor weight) roughly equivalent to that of the hypophysectomized rats. This resulted in a restriction to approximately ¾ of the normal food intake in the intact tumorbearing animals, while the hypophysectomized animals were given more food than they would have voluntarily consumed. At the time the glycogen samples were secured the hypophysectomized group had been deprived of pituitary tissue for 21 days. Liver, muscle, and tumor samples were taken in the order mentioned under amytal anesthesia 4 hours after the last feeding, and were frozen, weighed, and digested in the usual manner. Analyses were made according to the method of Good, Kramer and Somogyi 1 except that, in addition, the precipitate was washed once with 60% alcohol after being drained. The wash alcohol was also carefully drained off. The sugar in the final hydrolysate was determined by the Shaffer-Hartmann-Somogyi method. The percentage of glycogen present in the sample was calculated from this figure. For the tumors, glycogen was expressed as percentage of the total weight, or as mg. per sq. cm. of surface.
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