Metabolic Phenotyping Core

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Metabolic Phenotyping Core

The Metabolic Phenotyping Core provides state-of-the-art phenotypical measures to the scientific community at UMMC. Metabolic cages provide accurate measurements of whole metabolic information in rodents. Our metabolic capabilities offer access to Promethion metabolic screening (16 cages available), Columbus Instruments with environmental encloses (8 cages available), and AccuScan Instruments (8 cages)  in vivo test to help advance the metabolic characterization of genetic and pharmacological research models of metabolic diseases, circadian rhythms and more. Metabolic cages equipped with oxygen sensors to measure oxygen consumption (VO2) and infrared beams to determine motor activity.

VO2 will be measured for 30 sec-2-min at 10-minute intervals continuously 24-hours a day using an oxygen sensor. Motor activity is determined using infrared light beams mounted in the cages in X, Y and Z axes. Sleep time using duration of immobility of 40s is also available for rodents. The very small movements of the body associated with breathing during sleep are ignored in these measurements.

The XYZ arrays consist of high resolution (1 cm pacing) infrared beam arrays that are invisible to the animal (wavelength ca. 900 nm). The intensity of these beams are measured in rapid succession and movements are easily detected and a centroid-algorithm calculates the animal position and movements. After the mice or rats are acclimatized to the new environment, data are generally recorded for approximately 4-6 days, depending on the needs of the investigators.

In addition, our core performs physiological and non-invasive metabolic experiments to assess insulin sensitivity (glucose tolerance tests, insulin tolerance test, hyperinsulinemic-euglycemic clamp) to assess in vivo insulin action, insulin signaling and glucose metabolism (using labeled isotopes) in awake mice and rats as well as hyperglycemic clamp experiments to assess in vivo pancreatic beta-cell function and its effects on glucose metabolism.

Services

  • Whole Body Metabolic Assessment - To measure the caloric intake, feeding behavior, motor activity, energy expenditure, sleep time and fuel utilization of mice and rats. To understand mechanisms underlie rodent models of obesity and diabetes by measuring energy intake, expenditure, and partitioning aimed to define the whole body metabolic function.
  • Thermogenic Phenotyping - To measure the metabolic response of mice and rats to thermogenic challenges and to quantify heat generation by key thermogenic tissues. Heat generation is an important component of energy expenditure that acutely alters glucose utilization and long-term metabolism. Using telemetry to measure body temperature and standard and novel techniques, investigators can assess energy balance in mice and rats.
  • Body Composition Analysis - To provide robust measurements of body composition in live rodents. The total and relative fat and lean mass of an animal modulates whole body glucose, lipid and protein metabolism. Quantifying the body composition provides critical data for diabetes investigators as they assess the metabolic function and phenotypes of rats and mice. Precise body composition measurement of fat, lean, fat, free water and total water mass are measured using magnetic resonance imaging (4-in-1 EchoMRI-900TM, Echo Medical System, Houston, TX). EchoMRI scan is conducted in less than 50 seconds and can be carried out on mice and rats that are not sedated and provide reproducible results. We have available a horizontal bore for live rats up to 500, 700 or 1100 grams and 3 vertical bores, one for live mice up to 100grams, one for organs or tissue samples up to 7 grams and one biopsy sample up to 0.3 grams. EchoMRI analyzers are easy to operate and training period of one hour will be sufficient for most users
  • Measurement Metabolic Clamps - To measure insulin action, glucose disposal and production and insulin release in rodents. The defining feature of type 2 diabetes is reduced insulin action leading to hyperglycemia and altered lipid metabolism. Metabolic clamp studies permit measurement of insulin action, including the ability of key metabolic tissues to produce and clear glucose, and permit response of the pancreas to hyperglycemic stresses.


Contact Us

Dr. Jussara do Carmo, Core Director
Office: G261
Phone: (601)984-4353

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