[Characteristics of morphological reactions in dog internal organs and endocrine glands during 6-year gamma irradiation].

Dogs were exposed to six-year gamma-irradiation with doses of 21-1140 rad/year; pathomorphological changes were studied in testicles thyroid gland, adrenals, liver and kidneys. The level of morphological changes in the organs during the six-year exposure was dissimilar and depended on the radiosensitivity of a specific organ, dose rate and acute irradiations that were applied during the experiment. In testicles morphological changes (reduction of layers of the spermatogenous epithelium, decrease of the number of spermatozoids in testicular canals) appeared during the first year of irradiation at a dose rate of 0.34 rad/day. Later, these changes progressed and by the end of the six-year exposure were followed by a distinct sclerosis of the interstitial tissue and hyperplasia of Leydig's cells. In the thyroid gland signs of the hypofunctional state were seen by the end of the second year of irradiation at a dose rate of 0.34 rad/day and persisted afterwards. In adrenals hypertrophy of the bundle and glomerular zones were observed during the second-fourth years of irradiation at a dose rate of 0.34 rad/day. As irradiation proceeded hyperplastic processes developed in the thyroid gland and adrenals (adenomatous nodes in the thyroid gland, adenomatous hyperplasia in the adrenal cortex). Vacuolar and fat dystrophy of hepatocytes and disturbed permeability of glomerular capillaries in the kidneys were detected only at the end of the third year of irradiation. During the fifth and, particularly, the sixth year of the exposure sclerotic changes in the liver vessels, hyalinosis of small arteries and nephrosclerotic foci in the kidneys were found.