Pituitary hormone secretion after inhibition of L-aromatic amino acid decarboxylase activity in man.
The effect of acute administration of 200 mg benserazide, an L-aromatic amino acid decarboxylase inhibitor, on pituitary hormone secretion in humans was studied. Benserazide induced in all subjects a quick and marked increment of serum prolactin (Prl) and TSH levels: at 180 min TSH and Prl levels were still significantly higher than the baseline values. Women with normal menstrual cycles showed a Prl response to benserazide which was significantly greater than that observed in post-menopausal women and men. In another experiment six normal men received 10 mg of domperidone, a peripheral dopamine receptor blocker. The hormonal changes induced by domperidone were comparable to those obtained with benserazide. Since domperidone and benserazide are thought not to cross the blood-brain barrier, these results suggest that dopamine regulates Prl and TSH secretion through extra blood-brain barrier structures.
D000328:Adult; D001142:Aromatic-L-Amino-Acid Decarboxylases / Q000378:metabolism*; D001545:Benserazide / Q000494:pharmacology*; D001562:Benzimidazoles / Q000494:pharmacology*; D001812:Blood-Brain Barrier / Q000187:drug effects; D004294:Domperidone; D005260:Female; D006065:Gonadotropins, Pituitary / Q000097:blood; D006801:Humans; D006834:Hydrazines / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D010880:Piperidines / Q000494:pharmacology*; D010907:Pituitary Hormones / Q000378:metabolism*; D011388:Prolactin / Q000097:blood; D011954:Receptors, Dopamine / Q000187:drug effects; D013972:Thyrotropin / Q000097:blood
D001562:Benzimidazoles; D006065:Gonadotropins, Pituitary; D006834:Hydrazines; D010880:Piperidines; D010907:Pituitary Hormones; D011954:Receptors, Dopamine; D004294:Domperidone; D001545:Benserazide; D011388:Prolactin; D013972:Thyrotropin; D001142:Aromatic-L-Amino-Acid Decarboxylases