A Study of Adrenal Cortical Function in Acromegaly

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Abstract
Adrenal cortical function was studied in a group of patients with acromegaly. The secretion rate of cortisol (isotope dilution method) was elevated in both untreated females (24.0 and 34.2 mg/day) and in 2 of 3 patients undergoing conventional pituitary radiation (33.2 and 33.7 mg/day). The mean value for 10 patients treated with pituitary radiation was also elevated (27.2 mg/day; mean for 18 normal subjects, 10.9). In one female patient with acromegaly and coexisting thyrotoxicosis, cortisol production rate fell from a markedly elevated value of 34.5 to 21 mg/day, still a high value, after pituitary radiation and restoration of normal thyroid function. Of the 13 acromegalic patients, 5k had elevated 24-hr. urinary 17-ketosteroids and 9 had elevated 17-ketogenic steroids. Suppression of urinary steroid excretion by administered corticosteroid was adequate in the 9 patients so studied, and other indices of adrenal cortical function[long dash]response of plasma cortisol levels to ACTH[long dash]and diurnal variation of plasma cortisol levels[long dash]were generally normal. Administration of purified human growth hormone to a single control subject caused no increase in the secretion rate of cortisol; these data confirmed the observation of others. Therefore, no evidence could be adduced to support the idea that excessive secretion of growth hormone directly stimulated the adrenal cortex to secrete increased amounts of cortisol. The data indicate that some evidence of adrenal cortical hyperfunction is detectable in a majority of acromegalic subjects, despite treatment by conventional pituitary radiation.