Importance of extrahepatic sulphate conjugation.

A similar trend in the sulphate conjugation of isoprenaline and harmol was observed in the hepatic and three extrahepatic tissues, namely the kidney, small intestine and lung of some experimental animals. All the hepatic and some extrahepatic tissues exhibit this sulphating capability. In fact, some extrahepatic tissues, e.g. monkey lung, kidney and small intestine, mouse kidney and guinea-pig small intestine surpass their respective livers in this sulphate-conjugating reaction. When no or low activity was observed, a consistent pattern was found for both substrates. In general, isoprenaline is a better acceptor than harmol; the greatest difference was obtained with the mouse kidney preparation where an 18-fold difference was attributed partly to the higher sulphotransferase activity for isoprenaline than for harmol. The importance of extrahepatic sulphate conjugation is discussed.