Possible reasons why heavy drinking increases carbohydrate-deficient transferrin.

BACKGROUND: Transferrin is a globular protein synthesized in the liver that is responsible for iron transport in plasma. The structure of the molecule consists of two carbohydrate residues to which six sialic acid moieties can be attached. After periods of chronic, heavy alcohol consumption, carbohydrate-deficient transferrin (CDT) isoforms often increase, which makes CDT a useful marker in screening for alcohol abuse and monitoring progress of alcoholics in treatment. However, the precise mechanism behind CDT increase remains unknown.
METHODS: A review of the most relevant literature on CDT was conducted with a computer-assisted literature search.
RESULTS: During the past several years, a number of studies have explored possible mechanisms that may account for the alcohol-induced increase of CDT. An inhibition of protein synthesis and a general effect of alcohol on protein glycosylation have been reported. Although the exact mechanisms that underlie production of CDT are not yet fully understood, possible bases for the phenomenon are presented in this article.
CONCLUSIONS: Experimental findings indicate that the ethanol-induced effect on glycoprotein metabolism is a multistep process in which protein transport and changes of enzyme activity may play an important role.