ENZYMIC STUDIES ON MORPHINE GLUCURONIDE SYNTHESIS IN ACUTELY AND CHRONICALLY MORPHINIZED RATS

¹ Department of Pharmacology, State University of New York, Upstate Medical Center, Syracuse, New York

The enzymes responsible for glucuronide synthesis, namely, UDP-glucose pyrophosphorylase, UDP-glucose dehydrogenase, transferase, and NDP-kinase, were studied in livers of acutely and chronically morphinized rats. The activity of UDP-glucose dehydrogenase increased in both acutely and chronically treated rats as compared to those of control animals. The activity of transferase decreased as the animal received repeated doses of morphine. The enzymic activity of the other two enzymes was not appreciably altered. The relation of the changes in enzymic activities to the conjugating ability of the animal is discussed.

The data indicate a lack of relation between the formation of morphine glucuronide and the development of tolerance.