Episodic growth hormone secretion in the domestic fowl (Gallus domesticus): alpha adrenergic regulation.
In animals the secretion of GH is characterized by a series of spontaneous peaks. The situation in avian species, however, is unknown. The present study examines this in the domestic fowl. Blood samples were obtained via a remote catheter at 5-min intervals from young male chickens. An episodic pattern of GH secretion was observed having an interpulse interval (frequency) of approximately 1 h. Episodic GH secretion was altered by peripheral administration of drugs which influence adrenergic function. Spontaneous GH peaks were not observed following the administration of (1) bis-(4-methyl-1-homopiperazinyl-thiocarbonyl) disulfide (FLA63) or diethyldithiocarbamate (DDC) (which blocks norepinephrine (NE) and epinephrine (E) synthesis by inhibiting dopamine-beta-hydroxylase), (2) phenoxybenzamine (an alpha 1-adrenergic antagonist) and (3) clonidine (an alpha 2-adrenergic agonist). Neither alpha-methyl-p-tyrosine, which blocks dopamine (DA), NE and E synthesis, nor yohimbine, a predominantly alpha 2-antagonist could completely suppress episodic GH secretion. These data support a role for NE/E, acting via alpha adrenergic receptors, in the control of epidosic GH secretion in the domestic fowl.
D000818:Animals; D005406:Bis(4-Methyl-1-Homopiperazinylthiocarbonyl)disulfide / Q000494:pharmacology; D002645:Chickens; D003000:Clonidine / Q000494:pharmacology; D004050:Ditiocarb / Q000494:pharmacology; D013006:Growth Hormone / Q000378:metabolism*; D008297:Male; D008781:Methyltyrosines / Q000494:pharmacology; D010643:Phenoxybenzamine / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology*; D015016:Yohimbine / Q000494:pharmacology; D019805:alpha-Methyltyrosine
D008781:Methyltyrosines; D011942:Receptors, Adrenergic, alpha; D010643:Phenoxybenzamine; D005406:Bis(4-Methyl-1-Homopiperazinylthiocarbonyl)disulfide; D015016:Yohimbine; D019805:alpha-Methyltyrosine; D013006:Growth Hormone; D004050:Ditiocarb; D003000:Clonidine