[The function of thyroid glands subjected to deep freezing (--196 degrees)]

The function of the thyroid gland transplanted after being frozen to --196 degrees C was studied in experiments on rats. The gland was transplanted to thyroidectomized animals. Glands frozen without the use of cryoprotective agents and also in the presence of a cryoprotector--polyethyleneoxide with a mol. wt. of 400 (PEO-400) were used. Besides, a study was made of the effect of different rates of chilling on the thyroid gland. In assessment of the gland function a determination was made of tissue respiration, of I-131 consumption, and blood thyroid hormone content. To assess the cryoprotective effect of PEO-400 and for the choice of its optimal concentration the NMR method and roentgenostructural analysis werea applied. The thyroid gland proved to take and to retain its capacity to hormone formation after its freezing to the temperature of --196 degrees C according to a special program in the presence of PEO-400.