Nutritional efficiency of succinic acid and glutamic acid dimethyl
esters in colon carcinoma cells.
Zhang, Tie-Mei, Hassan Jijakli, and Willy J. Malaisse.
Laboratory of Experimental Medicine, Brussels Free University, B
-1070 Brussels, Belgium
APStracts 2:0256G, 1995.
The dimethyl ester of succinic acid (SAD) and glutamic acid (GME) were
found to be efficiently metabolized in colon carcinoma cells of the
Caco-2 line. The rate of [1,4-14C]SAD and [2,3-14C]SAD conversion to
radioactive acidic metabolites, CO2, amino acids, pyruvic acid and
lactic acid suggested that the catabolism of the ester-derived
succinic acid occurred mainly through the sequence of reactions
catalyzed by succinate dehydrogenase, fumarase and the malic enzyme.
This coincided with a marked sparing action of SAD on the utilization
of D-[2-3H]glucose and D-[5-3H]glucose and generation of 14C-labelled
acid metabolites, CO2 and lactic acid from D-[U-14C]glucose by the
enterocytes. Likewise, the conversion of [U-14C]GME to 14C-labelled
amino acids, its oxidation as compared to that of [1-14C]GME and the
production of NH4+ in the absence or presence of GME indicated
efficient catabolism of the latter ester. Like SAD, GME decreased the
utilization of D-[5-3H]glucose and generation of 14C-labelled acidic
metabolites, pyruvate and CO2 from D-[U-14C]glucose, whilst
increasing the generation of 14C-labelled amino acids from the
labelled hexose. The oxidation of D-[6-14C]glucose was even more
severely inhibited by GME. In normal rat intestinal cells, SAM, SAD
and GME also exerted a marked sparing action upon D-[U-14C]glucose
oxidation. The present findings suggest, therefore, that these esters
could possibly be used to sustain ATP generation in intestinal cells.
Received 22 March 1995; accepted in final form 30 November 1995.
APS Manuscript Number G123-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 December 95