Highly sensitive assay for phenylethanolamine N-methyltransferase in human brain
A rapid, highly sensitive assay for phenylethanolamine N-methyltransferase in brain using the natural substrate, norepinephrine, is described. The method is based on the selective adsorption and elution of the reaction product, epinephrine, from alumina. A small but important further lowering of blanks and increase in sensitivity is attained by removal of the radiolabeled substrate, (methyl-/sup 3/H)-S-adenosylmethionine by precipitation as the reineckate prior to adsorption of norepinephrine to alumina. The assay has a sensitivity of 30 fmole and the PNMT activity could be measured in as little as 1 mg (wet wt) of human locus coeruleus tissue. The sensitivity is enhanced by homogenizing tissue in small volumes and removing potential inhibitors by dialysis. We report for the first time PNMT activity in specific regions of the human cerebral and cerebellar cortex.
- Research Organization:
- St. Louis Veterans Administration Medical Center, MO
- OSTI ID:
- 5329804
- Journal Information:
- Proc. Soc. Exp. Biol. Med.; (United States), Journal Name: Proc. Soc. Exp. Biol. Med.; (United States) Vol. 1; ISSN PSEBA
- Country of Publication:
- United States
- Language:
- English
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62 RADIOLOGY AND NUCLEAR MEDICINE
ADRENAL HORMONES
AUTONOMIC NERVOUS SYSTEM AGENTS
BODY
BRAIN
CARDIOTONICS
CARDIOVASCULAR AGENTS
CENTRAL NERVOUS SYSTEM
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LABELLED COMPOUNDS
MEASURING METHODS
NERVOUS SYSTEM
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