Marked differences in functioning of the hypothalamicpituitary-adrenal axis between groups of men

Petrides, John S., Philip W. Gold, Gregory P. Mueller, Anita Singh, Costas Stratakis, George P. Chrousos, and Patricia A. Deuster.Marked differences in functioning of the hypothalamic-pituitary-adrenal axis between groups of men. J. Appl. Physiol. 82(6): 1979–1988, 1997.—To compare profiles of hypothalamic-pituitary-adrenal (HPA) responsiveness, healthy, moderately trained men ( n = 15) were classified as high ( n = 7) or low responders ( n = 8) on the basis of plasma adrenocorticotropic hormone (ACTH) responses to strenuous treadmill exercise 4 h after 4 mg of dexamethasone (Dex). These groups were then evaluated to compare 1) HPA and growth hormone responses to exercise at 90% maximal oxygen uptake 4 h after placebo, Dex (4 mg), and hydrocortisone (100 mg); 2) pituitary-adrenal responses to infusion of arginine vasopressin (AVP); 3) plasma cortisol after a Dex suppression test (1 mg); and 4) behavioral characteristics. In comparison to low responders, high responders exhibited significantly 1) higher plasma ACTH responses to exercise after placebo and Dex; 2) higher plasma AVP secretion with exercise after placebo and marked Dex- and hydrocortisone-induced enhancement of exercise-induced AVP secretion; 3) lower Dex-induced increases in basal and stimulated growth hormone secretion; 4) higher plasma ACTH responses to infusion of AVP; and 5) a trend ( P = 0.09) for higher trait anxiety ratings. Similar suppression of plasma cortisol was noted after 1 mg Dex. We conclude that subgroups of healthy male volunteers exhibit unique profiles of HPA responsiveness. We also believe that glucocorticoid pretreatment combined with strenuous exercise allows functional HPA responsiveness to be distinguished between subgroups of healthy controls and may be useful in the determination of susceptibility to disorders characterized by hyper- and hypo-HPA activation.

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The recovery of the hypothalamo-pituitary-ad renal axis after transsphenoidal operation in three patients with Cushing's disease. The effect of prior external pituitary irradiation

Acta Endocrinologica ◽

10.1530/acta.0.0980580 ◽

1981 ◽

Vol 98 (4) ◽

pp. 580-585 ◽

Cited By ~ 5

Author(s):

Steven W.J. Lamberts ◽

Jan G. M. Klijn ◽

Frank H. de Jong ◽

Jan C. Birkenhäger

Keyword(s):

Growth Hormone ◽

Cushing’S Disease ◽

Plasma Cortisol ◽

Hormone Secretion ◽

Growth Hormone Secretion ◽

Cushing's Disease ◽

Plasma Acth ◽

Basal Plasma ◽

Pituitary Irradiation ◽

Pituitary Adrenal Axis

Abstract. The recovery of the hypothalamo-pituitary-adrenal axis after selective transsphenoidal adenomectomy was studied in 3 patients with Cushing's disease by measuring basal plasma ACTH and cortisol concentrations, cortisol secretion rate, the diurnal rhythm of cortisol, and the reaction of cortisol to lysine vasopressin (LVP), of compound S to metyrapone and of cortisol and growth hormone to an insulin-induced hypoglycaemia. The third patient had been treated previously by external pituitary irradiation. In 2 patients basal plasma ACTH levels returned within normal values before plasma cortisol, but no supra-physiological plasma concentrations of ACTH were seen as has been observed after withdrawal of exogenous glucocorticoids. With regard to the different stimulation tests: at first the normal reaction of plasma cortisol to LVP returned after 3 months, at the same time as the restoration of growth hormone secretion in response to hypoglycaemia. A normalization of the reaction to metyrapone was seen thereafter while finally the reaction of cortisol to an insulin-induced hypoglycaemia and the diurnal rhythm of plasma cortisol returned 15 to 18 months after operation in the first patient and after 12 months in the second patient. Selective adenomectomy had also been carried out in the third patient, as evidenced by normal TSH, LH and FSH secretion. Hypocortisolism, and a deficient ACTH and growth hormone secretion in response to the stimuli mentioned, however, did not normalize up till 22 months after operation. The restoration of the hypothalamo-pituitary-adrenal axis after selective pituitary adenomectomy in Cushing's disease was prevented in this patient by prior external pituitary irradiation.

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