| SERVICE CORE | Test No. | Test Name | Price | Description |
| ANALYTICAL CORE | CA2015 | Turnover of glucose, lipid and/or protein | $200.00 / 4 samples / mouse | During a constant tracer infusion, the dilution of the infused tracer yields a measure of that molecule’s rate of appearance. One can measure the turnover of numerous molecules using this strategy. One can determine the kinetics glucose, glycerol and protein using [6,6-2H2]glucose, [2H5]glycerol and [2H5]phenylalanine.
This test requires a catheterized animal. |
| CA2016 | Fatty acid and cholesterol synthesis using 2H-labeled water | $75.00 / sample | Rates of fatty acid and cholesterol synthesis can be determined in tissues via the incorporation of 2H or 13C-labeled precursors. For example, following a bolus injection of 2H-labeled water one can collect samples (e.g. blood, liver and/or adipose tissue). The respective lipids are isolated and their 2H-labeling is determined. This test can be performed in 2 modes, short term vs long term. In a short term study, the tracer is administered and samples are collected within hours to determine the synthesis of lipids in plasma and/or liver. In a long term study, the tracer is continuously administered over several days. Samples of adipose tissue are collected. The difference in time scale is necessary since the pool of lipids in adipose tissue is relatively large and requires more time for label to appear.
Note: This test does not require catheterized mice, nor does it require that mice be shipped to the MMPC. The isotopes are non-radioactive and no special safety precautions are required, the tracers will be shipped from the MMPC to the investigator. Investigators will be instructed on how to administer the isotopes, collect samples and then ship them back to the MMPC. |
| CA2017 | Tissue-specific protein synthesis using 2H2O-labeled water | $150.00 / sample | Rates of protein synthesis can be determined from the incorporation of 2H-labeled water. For example, following a bolus injection of 2H-labeled water one can collect samples (e.g. blood, liver, muscle, etc). Total proteins are isolated and their 2H-labeling is determined. This test can be performed in 2 modes, short term vs long term. In a short term study, the tracer is administered and samples are collected within hours to determine the synthesis of proteins in plasma, liver, etc. This mode is well-suited for examining the acute response of protein synthesis to a perturbation (e.g. food intake). In a long term study, the tracer is continuously administered over several days. Samples are collected and the assays are performed. The long term design yields an integrative measure of protein synthesis, i.e. the isotope is present during the fed and the fasted state and accounts for all protein synthesis over such a transition.
Note: This test does not require catheterized mice, nor does it require that mice be shipped to the MMPC. The isotopes are non-radioactive and no special safety precautions are required, the tracers will be shipped from the MMPC to the investigator. Investigators will be instructed on how to administer the isotopes, collect samples and then ship them back to the MMPC. |
| CA2018 | Profile of acylcarnitines in plasma/urine tissue samples | $75.00/plasma or/urine sample $90.00/tissue sample | These LC-MS-MS assays are routinely run in which acylcarnitines are identified ac Cx, where x is the number of carbons in the acyl group. Samples are spiked with unlabeled and labeled internal standards. The mass isotopomer distribution of each peak is determined to characterize its labeling pattern.
This test, coupled with the assay of the profile of urinary organic acids helps in the characterization of a number of metabolic defects, such as inborn errors of fatty acid oxidation disorders. |
| CA2019 | Profile of long chain acyl-CoAs in tissue | $150.00 per sample [for concentration] | Commercial preparations of CoA and acyl-CoA contain an unnatural analog of CoA, iso-CoA, in which the 3’ phosphate has been moved to the 2’ position of ribose. We can use the acyl-iso-CoA esters as internal standards to calculate the concentration and mass isotopomer distribution of acyl-CoAs from LC-MS data. |
| CA2020 | Measurement of acetyl-CoA, propionyl-CoA and/or succinyl-CoA in tissue | $225.00/sample (concentration) and C13 labeling pattern | Commercial preparations of CoA and acyl-CoA contain an unnatural analog of CoA, iso-CoA, in which the 3’ phosphate has been moved to the 2’ position of ribose. We can use the acyl-iso-CoA esters as internal standards to calculate the concentration and mass isotopomer distribution of acyl-CoAs from LC-MS data. |
| CA2021 | Measurement of Methylmalonyl-CoA in tissue | $225.00/sample (concentration) and C13 labeling pattern | Commercial preparations of CoA and acyl-CoA contain an unnatural analog of CoA, iso-CoA, in which the 3’ phosphate has been moved to the 2’ position of ribose. We can use the acyl-iso-CoA esters as internal standards to calculate the concentration and mass isotopomer distribution of acyl-CoAs from LC-MS data. |
| CA2022 | 13C-Labeling pattern of acetyl moiety of citrate (substrate oxidation) | $110/sample | A number of investigators, who use 13C-labeled precursors of acetyl-CoA -in vivo- in isolated organs or in cell incubations, have attempted to estimate the labeling of mitochondrial acetyl-CoA to calculate the contribution of the substrate to the acetyl-CoA oxidized in the citric acid cycle (CAC). The best proxy for mitochondrial acetyl-CoA is the acetyl moiety of citrate.
We developed an assay of the labeling of the acetyl moiety of citrate which involves (i) tissue extraction, (ii) alkaline hydrolysis of extant acetyl-CoA, (iii) after pH adjustment, cleavage of citrate with CoA + ATP-citrate lyase which we isolated from rat liver.
The acetyl-CoA formed is either assayed as such by LC-MS, or reacted with thiophenol, followed by GC-MS assay of acetylthiophenol. This assay allows one to calculate the contribution of two or three substrates to mitochondrial acetyl-CoA in the same experiment.
For example, consider a mouse heart perfused with unlabeled glucose + [1-13C]palmitate + [U-13C4]acetoacetate.
These substrates yield acetyl-CoA that is unlabeled (M), singly labeled (M1), or doubly labeled (M2), respectively. So, the percent abundances of the M, M1, and M2 mass isotopomers of the acetyl moiety of citrate yield the contribution of each of the substrates to mitochondrial energy production. |
| CA2023 | Activity of acetyl-CoA carboxylase or malonyl-CoA decarboxylase in tissues | $75.00 per assay | • For acetyl-CoA carboxylase, the tissue extract is incubated with unlabeled acetyl-CoA + NaH13CO3 to form [13C]malonyl-CoA which, after hydrolysis, is assayed as its TMS derivative.
[U-13C3]Malonyl-CoA is used as an internal standard.
• For malonyl-CoA decarboxylase, we developed two different assays. The first assay involves incubation with [2-14C]malonyl-CoA, to form [2-14C]acetyl-CoA which is reacted with carnitine to form [2-14C]acetyl-carnitine the radioactivity of which is counted after isolation.
• The second assay involves incubation with [U-13C3]malonyl-CoA to form [1,2-13C2]acetyl-CoA. The latter is reacted with thiophenol, and acetylthiophenol is assayed by GC-MS, [2H3, 1-13C]acetyl-CoA is used as internal standard. |
| CA2024 | Metabolomic profile of citric acid cycle and gluconeogenic intermediates | $150.00 / sample [for concentration] | We will assay the relative concentration of citric acid cycle intermediates and those in the gluconeognic pathway. Assays can be run using samples from mice/organs that have also been infused with a 13C-labeled tracer, e.g. 13C-lactate. This strategy allows one to determine flux rates (via the 13C-labeling patterns) and identify points of control of a pathway, e.g. gluconeogenesis (via the relative concentration profiles). |
| CA2041 | Tissue processing by Pathology Core (embedded in paraffin) | | Tissue processing by Pathology Core (embedded in paraffin) |
| CA2042 | Tissue processing by Pathology Core (H&E staining) | | Tissue processing by Pathology Core (H&E staining) |
| CA2043 | Protal vein injection and tissue collection (at 0 min. & 5 min.) | | Portal vein injection and tissue collection (at 0 min. & 5 min.) |
| CA2044 | Brain uptake and bloodflow (includes femoral catherization) | | Brain uptake and blood flow (includes femoral catherization) |
| CA2045 | Measurement of ATP/ADP concentration in tissue | | Measurement of ATP/ADP concentration in tissues |
| CA2011 | Total Energy expenditure using 2H2O-labeled water | $100.00 / 4 samples / mouse | TEE is equal to the sum of basal metabolic metabolic, thermic effect of eating and physical activity. Following a single bolus injection of 2H and 18O-labeled water one can determine TEE via the elimination of 2H and 18O from body water. This test requires serial measurements of the labeling of body water over approximately 1 week, which necessitates the collection of blood or urine samples.
Note: This test does not require catheterized mice, nor does it require that mice be shipped to the MMPC. The isotopes are non-radioactive and no special safety precautions are required, the tracers will be shipped from the MMPC to the investigator. Investigators will be instructed on how to administer the isotopes, collect samples and then ship them back to the MMPC. |
