Cellular injury of adrenocorticotropic pituitary tumor (AtT-20) by corticosteroid in mice.
A transplantable ACTH-secreting pituitary tumor (AtT-20) in mice was studied for its growth in relation to adrenocortical steroid. The latency of transplanted tumor in LAF-1 mice with 10(6) tumor cells was about 2 weeks in adrenalectomized and in intact mice. In the former, however, tumor size reached 1.5 cm in diameter within 1 month, while it remained about 0.5 cm in the latter. Macroscopic and microscopic observation revealed that the tumor grafted in intact mice showed massive necrosis, leaving minimum intact tumor cells among necrotic foci. In contrast, the tumor grafted in adrenalectomized mice was healthy, soft, and showed adenomatous structure. It is concluded that excess of adrenocortical steroid produced in the grafted AtT-20 was inhibitory for the growth of transplanted tumor and removal of the adrenal glands was good for growth and survival of transplanted tumor. For the assessment of direct effect of adrenal steroid on AtT-20 cells, incorporation of 3H-thymidine in cultured AtT-20 cells was examined in a medium supplemented with glucocorticoid hormone. The autoradiographic study indicated that the inhibition of 3H-thymidine uptake was demonstrated at 24 hr after incubation with steroid and labeled cells were barely detectable on 3rd and 5th day.
D000236:Adenoma / Q000378:metabolism*; D000305:Adrenal Cortex Hormones / Q000494:pharmacology*; D000315:Adrenalectomy; D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D005260:Female; D008297:Male; D051379:Mice; D009336:Necrosis; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000378:metabolism; D010903:Pituitary Gland, Anterior / Q000648:ultrastructure*; D010911:Pituitary Neoplasms / Q000378:metabolism*
D000305:Adrenal Cortex Hormones; D000324:Adrenocorticotropic Hormone