INTERINDIVIDUAL VARIABILITY OF THE HUMAN HEPATIC SULFOTRANSFERASES

The variability among subjects of the hepatic activities of O-sulphotr ansferase towards dopamine, p-nitrophenol, testosterone and ethinyloes tradiol and of N-sulphotransfeiase with 1,2,3,4-tetrahydroisoquinoline (TIQ) as substrate is described. The rates of testosterone and TIQ su lphation were higher in men than women whereas those of ethinyloestrad iol, dopamine and p-nitrophenol were similar in both sexes. The sulpho transferase activities towards p-nitrophenol and dopamine were positiv ely skewed whereas those towards ethinyloestradiol approached normalit y. The coefficients of variations for the sulphotransferase activities ranged between 34% and 62% indicating a considerable variability amon g subjects. The rates of dopamine-, TIQ- and p-nitrophenol-sulphation were measured in the mucosa of the human intestine, and the duodenum/l iver ratios were 10, 0.9 and 0.1, respectively. Thus the contribution of the intestine in the sulphation of xenobiotics is substrate depende nt.