Wc. Song et al., ESTROGEN SULFOTRANSFERASE EXPRESSION IN THE HUMAN LIVER - MARKED INTERINDIVIDUAL VARIATION AND LACK OF GENDER SPECIFICITY, The Journal of pharmacology and experimental therapeutics, 284(3), 1998, pp. 1197-1202
Estrogen sulfotransferase (EST) catalyzes the specific sulfonation of
estrogen at the 3'-hydroxyl position using 3'-phosphoadenosine-5'-phos
phosulfate as an activated sulfate donor. Sulfonation renders the horm
one biologically inactive as well as changing its half-life within the
human body. Studies in the rat and mouse have suggested that expressi
on of EST in the liver is age-and sex-dependent, being prominent only
in sexually mature young males. Although a human EST cDNA has previous
ly been cloned, the characteristics of hepatic EST expression in human
subjects remain to be defined. In this study, we have investigated an
d compared the expression of EST in 10 human liver samples by using an
EST-specific antibody and performing enzyme activity assays. We found
a marked interindividual variation (up to 25-fold) in the hepatic exp
ression of EST. However, EST protein level in the human liver is corre
lated neither with gender nor with age. Interestingly, paired-group an
alysis revealed a statistically significant difference in the hepatic
expression of EST protein and activity between alcohol users and nonus
ers. We conclude that, unlike what is observed in the rodent liver, ES
T expression in the human liver is not sex-limited. Thus hepatic EST m
ay play a role in estrogen metabolism and homeostasis in both genders
of human subjects. The marked individual variation suggests that EST g
ene expression is subject to sensitive control by genetic or environme
ntal factors. The potential correlation between alcohol consumption an
d hepatic EST expression deserves further evaluation.