INDUCTION OF NEOPLASMS IN THE THYROID GLAND OF THE RAT BY X-IRRADIATION OF THE GLAND
The development of benign and malignant neoplasms was studied in thyroid glands of Long-Evans rats 2 years after either both lobes of the glands had been irradiated with 500, 1000, or 2000 r or the right lobe alone had been irradiated with 1000 r. The degree of follicular atrophy and of nuclear pleomorphism observed in these irradiated glands varied with the dose of x rays. Benign nodules or adenomas were observed in 30 of the 74 irradiated rats that survived. These lesions appeared to have originated as foci of nodular regeneration and hyperplasia. Papillary and follicular thyroid carcinomas were found in nine of the irradiated rats. Two of the six papillary carcinomas appeared to have originated in previously benign adenomas. Naturally occurring alveolar or lobular carcinomas had an incidence of 33% in normal control rats and of 22 to 45% in rats whose thyroids were irradiated with x rays. These naturally occurring carcinomas were of loiw-grade malignancy and were unlike those induced by irradiation. Parathyroid hyperplasia and adenomas were observed frequently in control as well as in irradiated rats. (auth)
- Research Organization:
- Univ. of California, San Francisco and Berkeley
- NSA Number:
- NSA-15-007208
- OSTI ID:
- 4119262
- Journal Information:
- Cancer Research, Journal Name: Cancer Research Vol. Vol: 21
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
Similar Records
INDUCTION OF NEOPLASMS IN THYROID GLANDS OF RATS BY SUBTOTAL THYROIDECTOMY AND BY THE INJECTION OF ONE MICROCURIE OF I$sup 13$$sup 1$
Primary hyperparathyroidism and nonmedullary thyroid cancer