Endocrine Abstracts

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...

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: Previous studies have shown that acylated ghrelin (AG) modulates insulin secretion and glucose disposal in vitro and after acute administration in humans. The aim of the present study was to evaluate postprandial glucose and insulin response following AG infusion in normal subjects and patients with type 2 diabetes.Methods: Six normal subjects and 3 patients with type 2 diabetes were included in this study. AG (1 μg/kg per h) or s...

Ghrelin circulates in two different forms. Acylated ghrelin (AG), a natural ligand of the GH Secretagogue receptor (GHS-R) type 1a, exerts several biologic central and peripheral actions including stimulation of GH secretion, but also modulation of insulin secretion, glucose and lipid metabolism. Unacylated ghrelin (UAG), despite unable to bind the GHS-R1a, is biologically active showing some influence in vitro and in vivo on glucose and lipid metabolism likely m...

Cortistatin (CST), a neuropeptide with high structural homology with somatostatin (SS), binds all SS receptor (SS-R) subtypes but, unlike SS, also shows high binding affinity to ghrelin (GRLN) receptor (GRLN-R). In humans CST exerts the same endocrine activities of SS, suggesting that the activation of the SS-R might mask the potential interaction with the GRLN system.CST-8, a synthetic CST-analogue devoid of any binding affinity to SS-R but capable to b...