Services

The Integrated Carbohydrate Physiology and Translation Laboratory offers several laboratory services for researchers. These services are available to collaborators both within and outside of Mayo Clinic.

Researchers interested in these services should contact lab directors for more detailed information about the services and their costs.

Here are the services offered by the lab:

Glucose clamps: Euglycemic, hypoglycemic and hyperglycemic

These tests are designed to accurately measure insulin sensitivity in a person with or without diabetes.

The technique involves infusing insulin intravenously at a constant rate over a few hours while maintaining blood glucose concentrations also at a predetermined concentration depending on the specific scientific questions posed.

Advancements in the methodology developed by Robert A. Rizza, M.D., of Mayo Clinic. and refined by the laboratory include simultaneous infusion of glucose tracers to partition insulin sensitivity into peripheral (muscle) or hepatic (liver) components. Infusing the hormone somatostatin simultaneously permits fine-tuning insulin concentrations so that the insulin sensitivity parameters can be compared between research study cohorts, for example, people with type 2 diabetes and those without diabetes.

Description: Regulation of hyperglycemia, euglycemia and hypoglycemia

Contact: basu.rita@mayo.edu or basu.ananda@mayo.edu

Oral glucose tolerance test

This physiologically pertinent method involves administering a 75-gram glucose drink together with periodic measurement of glucose and pertinent hormone concentrations (insulin, C peptide, glucagon, GLP-1) for two to three hours.

This method, coupled with physiological modeling developed in conjunction with mathematicians, provides measures of insulin secretion and insulin sensitivity.

Use of glucose tracers in the glucose drink could also help in partitioning of insulin sensitivity indices.

Description: Measurement of the body's ability to metabolize glucose

Contact: basu.rita@mayo.edu, basu.ananda@mayo.edu or kudva.yogish@mayo.edu

Intravenous glucose tolerance test

This method involves administering an intravenous glucose infusion followed, if necessary, by an insulin bolus, together with periodic measurement of glucose and pertinent hormone concentrations (insulin, C peptide, glucagon) for two to three hours.

This method, coupled with physiological modeling developed in conjunction with mathematicians, provides measures of insulin secretion and insulin sensitivity.

Use of glucose tracers allows partitioning of insulin sensitivity indices. A combination of both the oral glucose tolerance test (OGTT) and an IVGTT with an isoglycemic clamp (matching the glucose concentrations achieved during OGTT with an intravenous glucose infusion) could also provide valuable insight into the role of the incretin hormone GLP-1 on insulin secretion.

Description: Isoglycemic clamp

Contact: basu.rita@mayo.edu, basu.ananda@mayo.edu or kudva.yogish@mayo.edu

Mixed meal tests

This state-of-the-art methodology involves use of three different glucose tracers during a measured mixed meal test.

A research participant ingests a mixed meal containing glucose labeled with a glucose tracer while two other glucose tracers are infused intravenously at variable rates for six to seven hours.

During this time, periodic blood samples are drawn for measuring glucose, glucose tracer and hormone concentrations.

The data obtained can be used to measure insulin secretion and liver and peripheral insulin sensitivity.

This method is the most physiologically natural and relevant method that has been developed and validated in people with type 2 diabetes, people with type 1 diabetes and people without diabetes.

Description: Labeled triple tracer

Contact: basu.rita@mayo.edu, basu.ananda@mayo.edu or kudva.yogish@mayo.edu

Microdialysis

This method involves insertion of short, thin plastic catheters into the subcutaneous fatty tissue of the abdomen or thigh or both to measure various parameters depending on the scientific question.

The laboratory group has applied this technique to measure glucose transport and enzyme activity of 11-beta-hydroxysteroid dehydrogenase enzymes type 1 and 2 in the subcutaneous fatty tissue.

Description: Microdialysis

Contact: basu.rita@mayo.edu