Table 1.
Hepatic acetyl-CoA 13C-isotopomer abundances and fractional contributions of substrates to hepatic acetyl-CoA appearance in naturally feeding mice with their drinking water supplemented by two different concentrations of a 99% [1-13C]glucose/50% [U-13C]fructose mixture. *The estimated glucose contributions represent upper and lower limits based on the assumption that [1-13C]acetyl CoA was either entirely derived from [1-13C]glucose or from [U-13C]fructose, respectively.
Drinking water sugar levels (% w/v) | Acetyl 13C-isotopomer excess enrichments | Substrate contributions to acetyl CoA (%) | ||||
---|---|---|---|---|---|---|
[1-13C]acetyl | [2-13C]acetyl | [1,2-13C2]acetyl | Glucose* | Fructose | Endogenous | |
5% Fructose and 5% glucose (n = 4) | 0.4 ± 0.1 | 1.1 ± 0.1 | 2.0 ± 0.2 | 3.0 ± 0.2 | 4.0 ± 0.4 | 93.0 ± 0.4 |
1.4 ± 0.1 | 4.0 ± 0.4 | 94.6 ± 0.4 | ||||
| ||||||
17.5% Fructose and 17.5% glucose (n = 4) | 1.1 ± 0.1 | 2.6 ± 0.1 | 5.3 ± 0.3 | 7.4 ± 0.2 | 10.6 ± 0.6 | 82.2 ± 0.4 |
3.0 ± 0.1 | 10.6 ± 0.6 | 86.6 ± 0.4 |