Endocrine Abstracts

ITT is the test of reference for the diagnosis of adult GH deficiency (GHD), but it is recognized that also GHRH in combination with arginine (ARG) or GH secretagogues (GHS) are equally reliable tests. It has also been suggested that testing with GHS would represent a potent stimulus exploring also the integrity of hypothalamic pathways controlling somatotropic function. We therefore aimed to clarify the diagnostic reliability of testing with ghrelin, the natural GHS. We studi...

Growth hormone (GH) secretion is regulated by a complex interplay between GH-releasing hormone (GHRH), somatostatin and several other central and peripheral modulatory signals. Ghrelin has been hypothesized as physiological amplifier of GH pulsatility and acts via mechanisms, at least partially, independent of GHRH and somatostatin. The GH response to GHRH is strongly inhibited by previous administration of recombinant human GH (rhGH), likely as a consequence of a somatostatin...

Both hyper- and hypothyroidism show reduced spontaneous and GHRH-stimulated GH secretion. Although impaired GHRH secretion and activity as well as reduced GH pituitary synthesis have been reported in these pathological conditions, a definitive description of the underlying pathophysiological mechanisms have not been provided yet. Ghrelin elicits a potent GH-releasing effect partially mediated by a functional somatostatin antagonism and a synergic interaction with GHRH. Moreove...

Despite the common clinical opinion that thyrotoxicosis is associated with quantitative and qualitative sleep alterations, at present, an objective evaluation of sleep quality and quantity in this clinical condition has never been performed so far. Based on this foregoing, in order to perform a qualitative and quantitative description of sleep in this clinical condition, we enrolled 6 normal-weighted patients suffering from naïve overt hyperthyroidism due to Basedow Disea...

Background: Clinical reactive hypoglycemic events are defined as the coexistence of plasma glucose <60 mg/dl and autonomic and/or neuroglycopenic symptoms occurring in fed conditions. The diagnosis is based on tests aiming to simulate the causative triggers (i.e. mixed meal test). In clinical practice, however, a high percentage of symptomatic patients results negative to such diagnostic approach, leading to the impression of an inadequate sensitivity of this diagnostic to...

GH secretion is usually impaired in active Cushing’s syndrome (CS), due to concomitant mechanisms, including diminished GHRH and/or increased somatostatin release and impaired pituitary somatotrope responsiveness. Differently, IGF1 levels not parallel GH insufficiency in CS, being reported reduced, normal or increased. Both ghrelin and GHRH+arginine (ARG) are powerful GH secretagogues, influenced by age and/or BMI. In 27 CS (42.7±2.9 years, 28.8±0.9 kg/m2</...

Background: Obestatin, a ghrelin gene product was recently isolated but important questions remain regarding its regulation and its physiological effects. The aim of the present study was to evaluate the effect of unacylated ghrelin (UAG) on obestatin levels in normal subjects and patients with type 2 diabetes (T2D).Methods: Five normal subjects and 5 T2D patients were included in this study. Unacylated ghrelin (3 μg/kg per hour) or saline were cont...

Hyper- and hypo-thyroidism are considered as clinical conditions of sleep alterations. At present, however, these clinical reports have never been confirmed by studies providing a structured description of subjective and objective sleep quantity and quality. To this aim, we enrolled 15 patients with naïve overt hyperthyroidism (HYPER), 9 with naïve overt primary hypothyroidism (HYPO) and 15 healthy age-, sex- and BMI-matched control subjects (CS). Clinical conditions...

Background: The activation of the GHS-R1a receptor by acylated ghrelin (AG) or by synthetic GH secretagogues (GHS), potently stimulates GH release and mediates other neuroendocrine/metabolic effects. Beta-adrenergic receptor agonists negatively influence GH secretion and other metabolic functions. The GH response to AG and GHS is refractory to the inhibitory effect of β2-adrenoceptors activation but no other report has evaluated the interactions between AG and salbutamol ...

Background: Obestatin is a 27 aa peptide derived from the ghrelin gene. Obestatin was first described to exert anorexigenic effects by decreasing gastric motility in rodent models, however these results have been debated and there is presently only small information regarding its activity and its regulation in humans. Furthermore, its interactions with acylated ghrelin (AG), derived from the same gene, have not been evaluated. Therefore, in these preliminary data, we sought to...