Nervous Control of the Reaction of Anterior Hypophysis to X-Irradiation as Studied in Grafted and Newborn Rats

Publisher Website
Google Scholar
Abstract
The changes in ascorbic acid and cholesterol content of supra-renals grafted in the anterior chamber of the eyes of adrenalectomized rats are similar to those of normal rats after a total-body exposure to 850 r. The adrenal ascorbic acid of hypophysectomized rats with two pituitary grafts in each eye decreases 2 hours after 850 r, returns to normal at 24 hours, and does not show the 72 hour drop seen in irradiated controls. The adrenal cholesterol of these animals never drops but increases significantly at the third day. Suprarenals of newborn rats (aged 9 days maximum) do not react like those of adults to X-irradiation (600 to 800 r); they only show an increased cholesterol content on the third day after 800 r. The first adrenal reaction (2 to 3 hours after irradiation) is seen in young rats aged 10 to 13 days. The second reaction (3 to 4 days after irradiation), similar to that of adults, is not observed before 34 days of: age. X-irradiation does not act on pituitary directly, but through the hypothalamic centers which control the release of ACTH by the anterior hypophysis. The first reaction of the adrenals to a lethal X-irradiation is a typical reaction to stress, favorable to survival; the second reaction is not necessarily a sign of hypersecretion of corticoids; its presence has no relation to mortality or the severity of radiation sickness; the reactions of the suprarenals have only a small importance in the pathology of radiation sickness.