Alpha adrenergic control of growth hormone in adult male rats.
Intravenous injection of 0.1 mg/kg clonidine into rats under urethane anaesthesia induced a prompt and long-lasting release of growth hormone, estimated by radioimmunoassay (IRGH), which could be abolished by 0.2 mg/kg phentolamine given into the 3rd ventricle. Injection of 3 mug/kg clonidine into the 3rd ventricle stimulated also the release of IRGH significantly. Intravenous administration of 0.32 mg/kg phenylephrine caused a small and transient release of IRGH only. These results provide evidence that central alpha-adrenergic stimulation resulting in an increased GH secretion is one important mechanism in the regulation of this hormone in the rat.
D000818:Animals; D003000:Clonidine / Q000008:administration & dosage / Q000494:pharmacology*; D013006:Growth Hormone / Q000097:blood* / Q000378:metabolism; D007275:Injections, Intravenous; D007276:Injections, Intraventricular; D008297:Male; D010646:Phentolamine / Q000494:pharmacology*; D010656:Phenylephrine / Q000494:pharmacology*; D010902:Pituitary Gland / Q000187:drug effects*; D010903:Pituitary Gland, Anterior / Q000187:drug effects* / Q000378:metabolism; D051381:Rats
D010656:Phenylephrine; D013006:Growth Hormone; D003000:Clonidine; D010646:Phentolamine