ISSN:
1600-079X
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
An interaction between melatonin and adrenocorticotropin (ACTH) seems to occur in humans and both hormones respond to beta-adrenergic stimulation. As in lower animal species, human pineal gland also contains α2-adrenergic receptors as does the hypothalamus-pituitary axis. In this study the response of the pineal gland and of the hypothalamus-pituitary-adrenal axis to α2-adrenergic stimulation was assessed. Twenty-nine children (21 males, mean age 11.2±0.6 yr and eight females, mean age 9.1±1.1 yr) from the University of Granada Hospital were studied. The children were diagnosed as having growth problems but with a normal response of growth hormone (GH) to clonidine test. Changes in plasma levels of ACTH, cortisol and melatonin were evaluated in these children after oral administration of the α2-adrenoceptor agonist clonidine (100 μg/m2) or a placebo. Plasma ACTH, cortisol and melatonin were measured before (basal) and at 30, 60 and 90 min after oral clonidine or placebo administration. Hormonal determinations were carried out by commercial radioimmunoassay kits, previously standardised in our laboratory. The results show a significant decrease in plasma ACTH, cortisol and melatonin 30 min after clonidine administration (P〈0.001), reaching lowest values at 90 min after the drug was administered. The reduction in the levels of these hormones is independent of their normal circadian decay since the control group showed a significantly different pattern of behaviour. These data support the existence of an inhibitory α2-adrenergic influence on both the pineal gland and the hypothalamus-pituitary-adrenal in children and further support the presence of α2-adrenoceptors in the human pineal gland.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1034/j.1600-079X.2000.290107.x
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