TISSUE DISTRIBUTION OF HUMAN MONOAMINE OXIDASE-A AND OXIDASE-B MESSENGER-RNA

Abstract: Monoamine oxidase (MAO) A and B play important roles in the metabolism of biogenic amines. Northern analysis using 32P‐labeled subfragments of human liver MAO A and B cDNA clones detected a 5‐ and a 3‐kb transcript, respectively, in most human tissues examined. However, fetal heart and thymus express minute amounts of MAO A transcript, whereas fetal brain, muscle, thymus, spleen, meninges, and placenta express minute amounts of MAO B transcript. Small intestine and placenta express, in addition to the MAO A 5‐kb transcript, a 2‐kb transcript, which may arise from an alternative polyadenylation site. MAO A and B transcripts are expressed in similar regions of adult human brain. The highest concentrations of these transcripts were located in frontal cortex and locus coeruleus. This study demonstrates the tissue‐specific distribution of the MAO genes and will provide insight into the physiological functions of MAO A and B. Copyright © 1990, Wiley Blackwell. All rights reserved