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EFFECT OF ENHANCEMENT OF ENDOGENOUS CHOLINERGIC TONE WITH PYRIDOSTIGMINE ON GROWTH HORMONE (GH) RESPONSES TO GH‐RELEASING HORMONE IN PATIENTS WITH CUSHING'S SYNDROME
Author(s) -
LEALCERRO A.,
PEREIRA J. L.,
GARCIALUNA P. P.,
ASTORGA R.,
CORDIDO F.,
CASANUEVA F. F.,
DIEGUEZ C.
Publication year - 1990
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1990.tb00493.x
Subject(s) - pyridostigmine , endocrinology , medicine , somatostatin , cholinergic , growth hormone–releasing hormone , endogeny , hormone , growth hormone , myasthenia gravis
SUMMARY Growth hormone (GH) secretion in patients with Cushing's syndrome is diminished to all the stimuli tested so far but the precise mechanisms through which this occurs are unknown. In order to investigate whether increased somatostatinergic tone might be responsible for this alteration, we studied the effect of pyridostigmine (120 mg p. o. at ‐60 min), which activates cholinergic synapses and thus suppresses hypothalamic somatostatin release on GH responses to GHRH (100 μg, i. v. at 0 min), in six patients with Cushing's syndrome. We found that while pyridostigmine markedly potentiated GH responses to GHRH, in all the normal subjects tested (n=12), neither GHRH alone nor GHRH plus pyridostigmine elicited any increase in GH secretion in any of the patients with Cushing's syndrome. This suggests that chronic glucocorticoid excess induces marked alterations in the hypothalamic control of GH secretion.