“ 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.”