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Horm Metab Res 1985; 17(9): 443-447
DOI: 10.1055/s-2007-1013572
ORIGINALS
Basic
© Georg Thieme Verlag, Stuttgart · New York

Plasma Growth Hormone Responses to Microinfusion of Noradrenergic Agents into or Electrical Stimulation of the Hypothalamus and Amygdala in Baboons

J. R. McWilliam, B. S. Meldrum
  • Department of Neurology, Institute of Psychiatry, De Crespigny Park, London, United Kingdom
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Publication History

1984

1984

Publication Date:
14 March 2008 (online)

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Summary

In nine baboons (Papio papio) guide cannulae and electrodes were stereotaxically implanted into the medial basal or lateral hypothalamus, the anterior hypothalamus or the dorsal amygdala. Plasma GH responses were measured after microinfusion (1 μl) of the α2 adrenergic agonist, clonidine, or the β adrenergic antagonist, propranolol, or electrical stimulation, in each of these sites.

Clonidine, 100 nmol/μl, infused into the medial basal or lateral hypothalamus elevated plasma GH levels by 5-30 ng/ml, 30-45 min post-infusion. Plasma GH responses to clonidine infused into the anterior hypothalamus or the dorsal amygdala were all less than 10 ng/ml. The prior, intravenous, administration of piperoxane, 1.0 mg/kg prevented GH responses to clonidine.

Propranolol, 50 nmol/μl, infused into the dorsal amygdala consistently increased plasma GH levels by 5-15 ng/ml.

Electrical stimulation of the medial basal or lateral hypothalamus elevated plasma GH levels by 7-35 ng/ml, 15-45 min post stimulation. Electrical stimulation of anterior hypothalamus or dorsal amygdala did not alter plasma GH levels.

The stimulation of α2 adrenergic receptors in the medial basal or lateral hypothalamus of the baboons appears to facilitate GH release.

Key-Words:

Growth Hormone - α 2 -Adrenoceptors - Hypothalamus - Clonidine - Baboons

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