The response of corticotropin and adrenal steroids to desmopressin stimulation in patients with various forms of hypercortisolism.

OBJECTIVE: The purpose of this study was to evaluate the direct action of desmopressin (agonist of vasopressin) on the hypophysis and the three zones of the adrenal cortex in patients with different forms of hypercortisolism. DESIGN: Forty-three patients with hypercortisolism-21 with Cushing's disease (14 females, 7 males), 11 with extrapituitary, ectopic tumours (5 females, 6 males), and 11 with ACTH-independent Cushing's syndrome (6 females, 5 males)-were evaluated. The response of the pituitary and adrenal glands was assessed by measuring plasma levels of adrenocorticotropic hormone (ACTH), cortisol, aldosterone, and dehydroepiandrosterone sulfate (DHEAS) at baseline and at 15, 30, 60, 90, and 120 min after the administration of desmopressin. RESULTS: We observed two main modes of secretory response: (1) elevation of the ACTH level followed by a rise of one, two or all three adrenal steroids, and (2) ACTH-independent elevation of adrenal steroids in various combinations. CONCLUSION: In a number of patients with hypercortisolism, the adrenal cortex responded to desmopressin administration by enhanced synthesis and secretion of glucocorticoids (cortisol), mineralocorticoids (aldosterone), and adrenal androgens (DHEAS) without a concomitant rise in ACTH. These findings suggest the presence of "ectopic" vasopressin receptors in the human adrenal cortex.

Subclinical hyperthyroidism of variable etiology and its influence on bone in postmenopausal women.

OBJECTIVE: To evaluate the effects of subclinical hyperthyroidism of variable etiology on bone mineral density (BMD) and bone metabolism in postmenopausal women. DESIGN: T he study included data of 88 postmenopausal women classified into four groups depending on the etiology of subclinical hyperthyroidism: (1) 20 with toxic multinodular goiter without history of clinical hyperthyroidism; (2) 25 on levothyroxine suppressive therapy after thyroidectomy due to differentiated thyroid cancer; (3) 21 with Graves' disease (GD) receiving antithyroid drugs; (4) 22 healthy women matched for age and duration of menopause. In all subjects biochemical markers of bone turnover and B MD were determined. RESULTS: Biochemical markers of bone turnover were significantly higher (p-value =0.001) in all patients with subclinical hyperthyroidism compared to the control group (group 4). T he women of group 1 had significantly lower B MD at all regions of the skeleton, whereas the women of group 3 had significantly lower B MD at Total Hip (p-value = 0.013) and Radius Total (p-value = 0.0003) compared to group 4. No significant differences in B MD between groups 2 and 4 were detected. CONCLUSION: The etiology of subclinical hyperthyroidism influences B MD in postmenopausal women. Endogenous subclinical hyperthyroidism might be considered as an additional risk factor for osteoporosis in postmenopausal women, especially for cortical bone, whereas exogenous subclinical hyperthyroidism has no effect on BMD.