Has anyone come across this study before? It is about 50 years old and available as a free PDF download, pretty interesting stuff.
American Journal of Clinical Nutrition, Vol 8, 369-373, Copyright © 1960 by The American Society for Clinical Nutrition, Inc.
Effect of D-Glucuronic Acid and D-Glucuronolactone on Ascorbic Acid Levels in Blood and Urine of Man and Dog
EUGENE M. BAKER PH.D.1, EDWIN L. BIERMAN M.D.1, and IRVIN C. PLOUGH M.D.1
http://www.ajcn.org/cgi/content/abstract/8/3/369