Endocrine Abstracts

Glucocorticoids (GC) act at different target tissues by binding two different intracellular receptors, the glucocorticoid receptor (GR) and the mineralcorticoid receptor (MR), but the their effects vary considerably between subjects, due to a different sensitivity, which is at least partially, genetically determined. GCs are so named based on their actions on carbohydrate metabolism, namely on insulin-dependent processes. In particular, the effect of GC includes increased hepa...

Subclinical Cushing’s syndrome (SCS) is a status of altered hypothalamo-pituitary-adrenal (HPA)-axis secretion in the absence of the classical signs or symptoms of overt cortisol excess. Among the various tests used for the diagnosis of SCS, the 1-mg dexamethasone test (DST) is the most used. Alprazolam (ALP), a benzodiazepine activating GABAergic receptors, possesses clear centrally-mediated inhibitory effects on ACTH and cortisol secretion in normal subjects, while it d...

HPA is negatively regulated by glucocorticoid feed-back at hypothalamic, pituitary and hippocampal level by glucocorticoid (GR) and mineralcorticoid (MR) receptors. MR antagonists impair HPA rhythm after acute administration. The aim of this study was to verify HPA activity and glico-insulinemic profile both basally and after acute administration of potassium canrenoate (CAN), before and after chronic treatment. We evaluated ACTH, cortisol (F) and dehydroepiandosterone (DHEA) ...

Clinically silent adrenal masses discovered by abdominal imaging procedures performed for non-adrenal disorders, i.e. adrenal incidentalomas, have become a common finding in clinical practice and they represent a clinical concern because of the risk not only of malignancy but also of subclinical hormonal hypersecretion (SCS) that represents a new risk factor for cardiovascular diseases and/or osteoporosis. We studied 73 patients (39F, 34M; mean±S.E.M.: 61.6...

HPA response to glucocorticoids (GCs) feedback is usually tested by dexamethasone (DEX), a synthetic GC; it poorly crosses BBB and preferentially activates pituitaric glucocorticoid receptor (GR), with a binding potency to GR 7 fold higher and an anti-inflammatory potency about 35 fold higher than cortisol. Cortisol, which easily penetrates into CNS, could better evaluate the GC feedback by acting also at supra-pituitary level. We studied the effects of 150 min infusion of hyd...

Impaired GH secretion occurs in Cushing’s syndrome (CS), reflecting hypothalamic and pituitary alterations, without IGF-I impairment. Obesity is known to blunt GH release, leading to BMI-related tests for GHD. Evaluation of GH in CS after remission is difficult, due to chronic previous hypercortisolism and persistent overweight. Aim of this study was to evaluate in 22 patients with Cushing’s syndrome (16 Cushing disease, CD, 6 adrenal adenomas, CS) GH response to GHR...

Central serotoninergic activity (CSA) is known to influence the hypothalamus–pituitary–adrenal (HPA) axis, and a CSA loss seems to play a role in human brain aging and in etiology of functional hypercortisolism and depression, whose incidence increase with advancing age. Citalopram (CT), a SSRI, has been considered a good tool to evaluate CSA in humans. Aim of this study was to evaluate the neuroendocrine response to CT in healthy adult subjects during lifespan. We e...

In primary adrenal insufficiency hydrocortisone or cortisone are commonly used at doses of 30–37.5 mg/day as replacement therapy, though recent studies showed that cortisol normal production is about 5.7 mg/m2, equivalent to 20 mg/day of hydrocortisone, suggesting that supraphysiological doses are used. In 19 Addison’s disease patients (8 M, 11 F, 23–71 yr) under conventional glucocorticoid replacement therapy (37.5 mg cortisone/day) with low DHEAS le...

Insulin tolerance test (ITT) is considered the golden standard test to evaluate HPA axis in suspected hypopituitarism. Low dose (1 μg) ACTH1–24 short stimulation test (LDSST) and metyrapone are often used when ITT is contraindicated. The diagnostic reliability of LDSST is, however, controversial, as even this dose has been considered supramaximal, while very low ACTH doses have been suggested more reliable to assess the adrenal sensitivity. Thus, in...

Interrelationships between HPA axis and sleep architecture are well documented and increased glucocorticoid levels seem associated with quantitative and qualitative sleep disruptions. The knowledge about sleep parameters in chronic hypercortisolism in humans is scanty. Our aim was to evaluate sleep efficiency in patients with Cushing’s syndrome (CS) at time of diagnosis, without ongoing specific therapy, using wrist actigraphy, a methodology that provides good estimations...