Dehydroepiandrosterone sulfotransferase and estrogen sulfotransferase in human jejunum: Immunochemical characterization of individual variation

Sulfate conjugation, catalyzed by members of a gene superfamily of sulfotransferase (ST) enzymes, is an important metabolic pathway for many steroidt. Human tissues express at least five cytoplasmic ST enzymes, dehydroepiandrosterone (DHEA) ST, estrogen ST (EST) and three isoforms of phenol ST (PST). Individual variation in the expression of several of these enzymes is regulated by inheritance. We cloned cDNAs and genes and developed specific polyclonal antibodies for DHEA ST and EST in humans as a step toward molecular genetic experiments. DHEA ST and EST are both expressed in human small intestine. Therefore, we performed quantitative Western blot studies of 62 human jejunal mucosal samples obtained during clinically-Indicated surgery. Large individual variations in the quantity of DHEA ST and EST immunoreactive protein were detected that did not correlate significantly with time of tissue storage, patient age or gender. The jejunum was pathologically normal in 42 of these samples, while in 20 it was diseased. There were no significant differences between the two groups in immunoreactive DHEA ST or EST. Furthermore, immunoreactive DHEA ST and EST protein levels were not significantly correlated, indicating that they are regulated independently in human jejunum. These results represent a first step in the study of the molecular regulation of DHEA ST and EST expression in the human small intestine.