Noradrenaline and normetadrenaline metabolism in portal cirrhosis

Abstract

Four patients with moderate to severe portal (alcoholic) cirrhosis were injected intravenously with dl-noradrenaline-2-C14. Urine was collected via an indwelling catheter at 10-min intervals for 1 hr and thereafter for 6 and 24 hr. The metabolic products of noradrenaline were separated, identified, and their radioactivity measured. The same subjects were also injected with dl-normetadrenaline-1-C14, the O-methylated metabolic product of noradrenaline, and the urine samples similarly processed. The results seem to indicate that in portal cirrhosis noradrenaline metabolism is altered. In the period immediately following the injection of noradrenaline there is a slight decrease in the catechol-O-methyl transferase activity but thereafter it is either unchanged or slightly increased. Further, the cirrhotic shows a distinct predilection for conjugating both noradrenaline and normetadrenaline. This is reflected by a significant increase in the sulfate conjugate of both of these compounds. The monoamine oxidase activity is decreased slightly throughout the collection periods. This is reflected by a decrease in the formation of 3-methoxy-4-hydroxymandelic acid following an injection of both noradrenaline and normetadrenaline.