Serotonin vascular reactivity and other clinical pharmacological investigations in two intestinal carcinoid patients.
In two patients with carcinoid syndrome, a reduced venoreactivity to serotonin (5-HT) was found by means of the venoconstriction test. Parachlorophenylalanine (PCPA) treatment increased 5-HT venoreactivity. A normal noradrenaline venoreactivity was detected before and during PCPA administration. The altered platelet monoamine oxidase (MAO) activity corrected by PCPA treatment. The abnormal 5-HT turnover may alter the synthesis of MAO and provoke the production of isoenzymes. Low plasma amine oxidase and high plasma histaminase activity were found in 1 of these 2 patients. A low level of plasma prekallikrein in the two patients remained unchanged during PCPA administration.
D006631:Amine Oxidase (Copper-Containing) / Q000097:blood; D010134:Fenclonine / Q000494:pharmacology; D006801:Humans; D007414:Intestinal Neoplasms / Q000201:enzymology / Q000503:physiopathology*; D008995:Monoamine Oxidase / Q000097:blood; D009638:Norepinephrine / Q000494:pharmacology; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000097:blood; D011288:Prekallikrein / Q000097:blood; D012701:Serotonin / Q000494:pharmacology*
D012701:Serotonin; D011288:Prekallikrein; D006631:Amine Oxidase (Copper-Containing); D008995:Monoamine Oxidase; D000587:Oxidoreductases Acting on CH-NH Group Donors; D010134:Fenclonine; D009638:Norepinephrine