Bromocriptine suppression of TRH-stimulated prolactin and thyrotrophin release and accompanying inhibition of bromocriptine induced growth hormone release by TRH in normal man.
Six normal fasting males received on four separate occasions in random order (1) a placebo tablet followed 60 min later by 200 microgram of TRH intravenously (2) bromocriptine 2.5 mg orally followed by TRH intravenously (3) bromocriptine 2.5 mg orally followed by a placebo injection and (4) placebo tablet followed by placebo injection. Plasma prolactin and TSH responses to TRH were decreased following bromocriptine pretreatment. The rise of plasma growth hormone after bromocriptine was inhibited by TRH. The rise in plasma FSH seen after TRH injection was not influenced by bromocriptine pretreatment. Circulating LH and insulin concentrations were unaffected by any drug administration. These results suggest a dopaminergic influence on prolactin and TSH release in normal men, an inhibitory effect of TRH on bromocriptine stimulated growth hormone secretion, and no dopaminergic modulation of basal insulin secretion.
D000328:Adult; D001971:Bromocriptine / Q000494:pharmacology*; D005640:Follicle Stimulating Hormone / Q000097:blood / Q000378:metabolism; D013006:Growth Hormone / Q000097:blood / Q000378:metabolism*; D006801:Humans; D008297:Male; D011388:Prolactin / Q000097:blood / Q000378:metabolism*; D012636:Secretory Rate / Q000187:drug effects; D013972:Thyrotropin / Q000097:blood / Q000378:metabolism*; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*
D001971:Bromocriptine; D013973:Thyrotropin-Releasing Hormone; D011388:Prolactin; D005640:Follicle Stimulating Hormone; D013972:Thyrotropin; D013006:Growth Hormone