Neuroendocrine effects of L-tryptophan and dexamethasone.
An infusion of L-tryptophan was administered twice to five healthy male volunteers, once after pretreatment with dexamethasone 1 mg the previous evening and once after no dexamethasone. Cortisol, prolactin, and growth hormone levels were measured, and the responses to L-tryptophan were compared with those seen after an infusion of L-threonine. L-tryptophan did not produce cortisol secretion after dexamethasone, but prolactin and growth hormone responses were noticed. The results demonstrate a stimulatory effect of L-tryptophan on prolactin and growth hormone secretion, and the former is facilitated by pretreatment with dexamethasone.
D000328:Adult; D003907:Dexamethasone / Q000494:pharmacology*; D013006:Growth Hormone / Q000097:blood*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D008297:Male; D011388:Prolactin / Q000097:blood*; D013912:Threonine / Q000494:pharmacology; D014364:Tryptophan / Q000494:pharmacology*
D013912:Threonine; D003907:Dexamethasone; D014364:Tryptophan; D011388:Prolactin; D013006:Growth Hormone; D006854:Hydrocortisone