Center for Metabolism
and Mitochondrial Medicine
Metabolism Unit
The mission of Metabolism Unit is to make available platform technologies, training, and study design and data analysis expertise for in vivo, ex vivo, and in vitro metabolic studies in rodent and cell culture models. The expertise of the unit extends from assessment of metabolic flux, energy expenditure, body composition, insulin sensitivity, exercise capacity, and insulin signaling in the whole animal, to the performance of metabolic, biochemical, and molecular studies in primary and immortal cell culture models of relevance to metabolic diseases. The unit is based on the 10th floor of the Biomedical Science Tower.
Michael Jurczak, PhD
Director
Platform Technologies
Mouse Metabolic Cage Studies
The major determinants of energy balance including feeding, drinking, activity, energy expenditure and respiratory exchange ratio are measured using the Sable Systems Promethion Multiplexed Metabolic Cage System. The system can accommodate 16 mice and is housed in two temperature controlled cabinets that enable studies performed at room temperature, thermoneutrality or cold conditions. Additional features include running wheel capability, time restricted or paired feeding, and behavioral assessments such as food preference and time allocation.
Mouse Body Composition
An EchoMRI body composition analysis system allows for measures of whole body fat, lean, free water, and total water mass in living, conscious animals. Results can be obtained from organs or mice (up to 130 g) in as little as 30 seconds.
Exercise Testing with CLAMS
Acute exercise testing in mice can be performed using a single-lane air-tight enclosed treadmill used in conjunction with the CLAMS for respiratory metabolic assessment during exercise. Integrated software allows for user-defined protocol interval and speed determination. The unit also features incline capability in 5° increments.
Exercise Testing in Open Air
Acute or chronic (training) exercise protocols can be performed in an open-air treadmill featuring three (rats) or six (mice) lanes, and includes adjustable incline capabilities (0-25°). User-friendly software allows for user-defined protocols, adjustable acceleration (in 0.1 meter/minute-steps per second), and wide range of speed (3-100 meters/minute). Data are exported in .csv format.
Bomb Calorimetry
The use of bomb calorimetry allows for the assessment of energy content in both food and/or feces to determine the energy intake of study animals. The Parr 6200 is an isoperibol oxygen bomb calorimeter that can analyze 8-9 samples per hour.
Mitochondrial Respiration
“Four Oroboros O2K units (eight chambers total) are used for high-resolution respirometry and the quantitative assessment of oxygen flux in biological samples, including permeabilized muscle fibers from human or rodent biopsies, permeabilized cells, purified mitochondria or mitochondrially enriched lysates from cells or human or rodent tissue. The units are also fitted with fluorometric sensors allowing integrated measures of reactive oxygen species, mitochondrial membrane potential, and ATP production alongside oxygen consumption. Multiple substrate-uncoupler-inhibitor protocols (SUIT) can be applied to assess specific aspects of mitochondrial bioenergetic capacity.
Insulin Sensitivity by Hyperinsulinemic Euglycemic Clamp
The hyperinsulinemic euglycemic clamp is the gold-standard for determining insulin sensitivity in vivo. By using metabolic isotopic tracers during clamp, whole-body and tissue-specific rates of carbohydrate and lipid metabolism can be measured under fasted and insulin-stimulated conditions in transgenic mice. Key parameters measured: basal rates of hepatic glucose production and whole-body glucose utilization; insulin-stimulated rates of hepatic glucose production and whole-body glucose uptake; tissue-specific rates of glucose uptake; fasting and insulin-stimulated plasma fatty-acid levels and palmitate turnover as indices of adipose tissue insulin sensitivity.
Staff
Contact
Michael Jurczak, PhD | jurczakm@pitt.edu
Rob O’Doherty, PhD | rmo1@pitt.edu
