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Secretion of growth hormone (GH) is excessive in acromegaly, but also in a number of other pathological states such as anorexia nervosa, insulin-dependent diabetes mellitus (IDDM), liver cirrhosis, depression, renal failure and GH-insensitivity syndrome. Abnormalities in the neuroendocrine control of GH secretion and/or a state of insensitivity to GH contribute to hypersecretion of GH in these states, with the possible exception of acromegaly, which appears to be a primary pituitary disease. GH hypersecretion may also occur in neonates or adolescents with tall stature, thus reflecting particular physiological or paraphysiological conditions. In the cohort of brain neurotransmitters, catecholamines and acetylcholine reportedly play a major role in the control of neurosecretory GH-releasing hormone (GHRH) and somatostatin (SS)-producing neurons, and hence GH secretion. Activation of alpha 2-adrenoceptors or of muscarinic cholinergic receptors in the hypothalamus stimulates GH release, probably through stimulation of GHRH and inhibition of SS release, respectively. Activation of dopamine receptors likewise stimulates GH release, while activation of beta-receptors inhibits GH release through stimulation of hypothalamic SS function. This review discusses the involvement of brain catecholamines and acetylcholine in GH hypersecretory states, including anorexia nervosa, acromegaly, IDDM, liver cirrhosis, depression, renal failure and GH insensitivity syndrome, with a view to providing a fuller understanding of their pathophysiology and, whenever possible, diagnostic and therapeutic implications.

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Background. The aim of this observational study was to investigate for which nodules a better response to radiofrequency thermoablation (RFA) for nonfunctioning benign thyroid nodules is likely. Methods. Aesthetic score, compressive score, and volume of 32 benign nodules from 32 patients were registered during follow-up at baseline, 1, 3, 6, and 12 months. Results. A volume reduction rate (VRR) of 72.56% at 12 months after the procedure ( P = .009) was registered. A significant ( P < .001) improvement in the compressive and aesthetic scores was observed. Nodules with a baseline volume <20 mL had VRRs at 3 and 6 months that were significantly greater than those with volume >20 mL ( P = .037). Conclusions. RFA was shown to be a safe and effective procedure for the management of benign thyroid nodules and that there is a correlation between the initial size of the nodule and the response to treatment.