Histamine formation from 14 C-L-histidine in man

Area of Science:

• Biochemistry
• Hematology
• Oncology

Background:

• Histamine is a biogenic amine with diverse physiological roles.
• Altered histamine metabolism may be associated with hematological malignancies.

Purpose of the Study:

• To investigate histamine metabolism in patients with chronic myelocytic leukemia (CML).
• To quantify histamine and metabolite production in CML compared to normal subjects.

Main Methods:

• Administered intravenous (14)C-L-histidine to one normal subject and two CML patients.
• Measured urinary and blood levels of (14)C-histamine and its metabolites (methylhistamine, methylimidazoleacetic acid).
• Monitored total (14)C elimination via urine and lungs.

Main Results:

• CML patients showed significantly higher blood levels of (14)C-histamine post-administration.
• Excretion of (14)C-labeled histamine metabolites was substantially greater in CML patients.
• Estimated daily histamine formation in CML patients was at least 20 times higher than in the normal subject.
• Total (14)C elimination exhibited a plateau in CML patients between days 10-14.

Conclusions:

• Chronic myelocytic leukemia is associated with markedly increased histamine synthesis.
• Elevated histamine production may be a metabolic characteristic of CML.
• Further research is warranted to explore the clinical implications of altered histamine metabolism in CML.