Summary
An extensive hypothalamic neurotransmitter impairment has been proposed in acromegaly.
However, at the moment, the hypothalamic GABAergic system has been little investigated
in this disorder. Since GABA has been shown to modulate growth hormone (GH) and prolactin
(PRL) secretion in human subjects, it seemed reasonable to investigate hypothalamic
GABAergic functioning through the assessment of basal GH and PRL responses to pharmacological
activation of this system. 800 mg of sodium valproate (SV), a drug with GABA facilitating
properties, were administered orally to 7 acromegalic patients and 9 healthy volunteers.
Blood samples were collected before and after the drug administration for the measurement
of plasma GH and PRL levels. SV induced a clear-cut rise in basal GH and a decrease
in basal PRL in healthy subjects, but it did not induce any change in the basal levels
of these hormones in acromegalics. These results suggest that the response of GH and
PRL to SV in acromegaly is qualitatively different from normal controls.
Key-Words
Acromegaly
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GABA
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Growth Hormone
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Prolactin
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Sodium Valproate
