Me. Christe et Rl. Rodgers, ALTERED GLUCOSE AND FATTY-ACID OXIDATION IN HEARTS OF THE SPONTANEOUSLY HYPERTENSIVE RAT, Journal of Molecular and Cellular Cardiology, 26(10), 1994, pp. 1371-1375
Metabolic fuel oxidation may be altered in left ventricular hypertroph
y (LVH), but detailed characterizations are lacking. Although the spon
taneously hypertensive rat (SHR) is a widely used experimental model o
f LVH, its myocardial fuel oxidation rates are unknown. The purpose of
this study was to directly measure glucose and fatty acid (FA) oxidat
ion in the SHR heart: ex vivo under controlled loading conditions. Hea
rts from 15-week-old SHR and Sprague Dawley (SD) rats were perfused in
a recirculating system and indices of cardiac performance were contin
uously monitored. The oxidation of glucose and palmitate were determin
ed simultaneously at low and high workloads by the addition of U-C-14-
glucose and 9,10-H-3-palmitate to the recirculating perfusate. The res
ults demonstrate that FA oxidation of SHR hearts is profoundly suppres
sed (60-80%) relative to that of the normotensive SD strain, particula
rly at high workloads. Glucose oxidation is also moderately elevated,
yielding a marked (four-to-five-fold) increase in tile ratio of glucos
e/FA oxidation rates in the SHR hearts. Since more ATP is generated pe
r mole of oxygen consumed when glucose is the fuel scource, these resu
lts are consistent with the hypothesis that a shift away from FA use t
oward glucose contributes to the preservation of energetic economy in
stable, concentric LVH.