Hormonal response to L-tryptophan infusion: effect of propranolol.
There is circumstantial evidence that increases in prolactin secretion evoked by L-tryptophan infusion involve 5-HT1 receptors, whereas growth hormone responses do not. Propranolol is a beta-adrenoceptor antagonist that also possesses antagonist properties at 5-HT1 receptors. Propranolol (80 mg, PO) failed to attenuate the prolactin response to L-tryptophan infusion (100 mg/kg, IV) in seven volunteers; the role of 5-HT1 receptors in this response remains uncertain. The growth hormone response to tryptophan was enhanced by propranolol, consistent with previous reports of an inhibitory beta-adrenoceptor influence on GH secretion. Excessive beta-adrenoceptor function might explain the blunted growth hormone response to tryptophan in depression.
Upadhyaya
A K
AK
Department of Psychiatry, Withington Hospital, Manchester, U.K.
Deakin
J F
JF
Pennell
I
I
D000328:Adult; D001143:Arousal / Q000187:drug effects*; D013006:Growth Hormone / Q000097:blood*; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D011388:Prolactin / Q000097:blood*; D011433:Propranolol / Q000494:pharmacology*; D011985:Receptors, Serotonin / Q000187:drug effects; D014364:Tryptophan / Q000494:pharmacology*
D011985:Receptors, Serotonin; D014364:Tryptophan; D011388:Prolactin; D013006:Growth Hormone; D011433:Propranolol