Endocrinology, Vol 114, 2406-2408, Copyright © 1984 by Endocrine Society

ARTICLES

Inhibitory action of the alpha 1-adrenergic receptor on growth hormone secretion in the dog

SG Cella, M Morgese, P Mantegazza and EE Muller

Intravenous administration of methoxamine ( METHOX , 5 mg, iv), a specific alpha 1-adrenergic agonist, reduced baseline GH levels of four unanesthetized beagle dogs 45 and 60 min post-injection and completely abolished the GH-releasing effect of the alpha 2-adrenergic agonist clonidine ( CLON , 4/ micrograms/kg, iv). Prazosin (PRA, 0.1 mg/kg, iv), an alpha 1-adrenergic antagonist, administered before METHOX re- instituted the GH-releasing effect of CLON . METHOX administered at the starting of an arginine infusion (ARG, 10% solution, 3.3 ml/min X 30 min) reduced consistently the GH releasing effect of the latter while, conversely, pretreatment with PRA, strikingly potentiated the GH- releasing effect of the amino acid (2 dogs). METHOX did not alter the GH-releasing effect of human pancreatic GH-releasing factor (hpGRF-40, 1/microgram/kg, iv), though it consistently delayed the occurrence of the GH secretory peak following hpGRF-40. These data indicate that alpha 1-adrenergic receptors located in the central nervous system, inhibit in the dog tonic and stimulated GH secretion.

This article has been cited by other articles:

				E. E. Muller, V. Locatelli, and D. Cocchi Neuroendocrine Control of Growth Hormone Secretion Physiol Rev, April 1, 1999; 79(2): 511 - 607. [Abstract] [Full Text] [PDF]