Hepatic production of 1,5-anhydrofructose and 1,5-anhydroglucitol in rat by the third glycogenolytic pathway.
A unique anhydrohexulose, 1,5-anhydrofructose (1,5AnFru) has been detected in rat livers. Here we describe a microanalytical method for 1,5AnFru using GC/MS and report results on the distribution and production of 1,5 AnFru in rats. The highest levels of 1,5AnFru were found in the liver (0.43 microgram/g wet tissue) and appreciable amounts were detected in adrenal gland and spleen (0.12 microgram/g and 0.09 microgram/g, respectively). Other organs contained lower amounts while plasma contained virtually no detectable 1,5AnFru. We also demonstrated that 1,5AnFru is produced in the cytosol fraction of rat liver homogenate when an alpha-1,4-glucan or glycogen was added; 1,5AnFru was readily reduced to 1,5-anhydroglucitol with NADPH or at a reduced efficiency with NADH in the presence of a Mono Q chromatographic fraction obtained from the same cytosol preparation. Based on these results, we propose the existence of a third degradation pathway, in addition to the phosphorolytic and hydrolytic reaction sequences, from glycogen to 1,5-anhydroglucitol via 1,5AnFru in mammals. However, the physiological significance of 1,5AnFru and this putative minor glycogenolytic pathway in mammals remains obscure.
Kametani
S
S
Department of Life Science (Chemistry), Graduate School of Arts and Sciences, University of Tokyo, Japan.
Shiga
Y
Y
Akanuma
H
H
D000818:Animals; D003847:Deoxyglucose / Q000378:metabolism*; D005632:Fructose / Q000031:analogs & derivatives* / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D005936:Glucans / Q000378:metabolism; D006003:Glycogen / Q000032:analysis; D008297:Male; D008722:Methods; D010084:Oxidation-Reduction; D010091:Oximes / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar; D014018:Tissue Distribution
D005936:Glucans; D010091:Oximes; D005632:Fructose; C006584:1,5-anhydroglucitol; C048927:1,5-anhydrofructose; D006003:Glycogen; D003847:Deoxyglucose