Inhibition of L-dopa-induced growth hormone stimulation by pyridoxine and chlorpromazine.
One gram of L-dopa was administered orally to 12 male control subjects and induced an increase of growth hormone (GH) secretion. The L-dopa-induced GH response was inhibited by an intravenous infusion of pyridoxine, but pyridoxine did not inhibit the GH response to hypoglycemia. Chlorpromazine also inhibited L-dopa-induced GH stimulation. Glucose concentrations were unaffected by L-dopa, chlorpromazine, and pyridoxine administration in these subjects. The mechanism of the suppressed L-dopa-induced GH response by pyridoxine appears to be mediated by peripheral accleration of the conversion of L-dopa to dopamine, while that of chlorpromazine appears to be mediated through hypothalamic centers. Pyridoxine and chlorpromazine should be added to the list of other factors affecting the response to L-dopa-induced GH stimulation
D000328:Adult; D001786:Blood Glucose; D002746:Chlorpromazine / Q000494:pharmacology*; D013006:Growth Hormone / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D007980:Levodopa / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D011736:Pyridoxine / Q000494:pharmacology*; D013268:Stimulation, Chemical
D001786:Blood Glucose; D007328:Insulin; D007980:Levodopa; D013006:Growth Hormone; D011736:Pyridoxine; D002746:Chlorpromazine