The effects of hypobaric hypoxia on the corticotroph population of the adenohypophysis of the male rat.

The effect of hypobaric hypoxia on the corticotroph population of the adenohypophysis has been studied in male rats. After 28 days exposure to a barometric pressure of 380 mm Hg, equivalent to an altitude of 5500 m, there was an increase in their number relative to the total cell population. This may reflect a requirement for a sustained increase in the level of adrenocortical secretion in an hypoxic environment. Alternatively, higher levels of ACTH may be required to maintain normal levels of adrenocortical hormone secretion under these conditions.