Water in normal muscle and muscle with a tumor.

The total water content, the amount of non-freezable water, and the Na-+ and K-+ contents in the gastrocnemius muscle of albino mice with and without a solid tumor were determined. The spin-lattice relaxation time (T1) for the water protons in the two kinds of muscle were measured at six resonance frequencies ranging from 4.5 to 60 MHz over the temperature range +37 to minus 65 degrees C. Quantitatively calculated T1 values are given. The difference in T1 for the two types of muscle at temperatures above minus 5 degrees C is attributed to the difference in the distribution ratio of water between hydration and free states, and bears no direct relation to the concentration of Na-+.