The hyperglycemic clamp assay and the hyper-insulinemic euglycemic clamp assay are the gold standards for assessing the sensitivity of β cells to insulin and the effects of insulin, respectively. They are usually used to evaluate the glucose metabolism status of mice. Both these two experimental techniques detect the metabolic process of glucose and the function of insulin in tumor-bearing mice under a stable blood sugar state through the variable infusion of glucose or insulin. CD BioGlyco provides hyperglycemic clamp and hyper-insulinemic euglycemic clamp assays services to assess the ability of insulin secretion and β cell function in awake tumor-bearing mice.

Experimental Principle

The hyperglycemic and hyper-insulinemic euglycemic clamp assays are designed based on a glucose-insulin negative feedback system. The hyperglycemic clamp assay to assess pancreatic response to hyperglycemia. When the body's blood sugar rises, insulin secretion increases and the body lowers blood sugar by increasing the uptake, storage, and utilization of glucose. When the body's blood sugar drops, insulin secretion decreases, glucagon secretion increases, and the body raise blood sugar by promoting metabolism and accelerating glycogenolysis and gluconeogenesis pathways.

Fig. 1 The hyperglycemic clamp assays profile (Gerst F, et al., 2018)

Our Workflow

• The workflow of hyperglycemic clamp assay as following:

1. The tumor-bearing mice undergo hyperglycemic clamp experiments for two hours after a 12-hour fast.
2. The hyperglycemia clamp experiment starts with the initial dose of glucose infusion. The goal of the initial dose of glucose infusion is to make the body quickly reach the target hyperglycemia. Generally, the target hyperglycemia value is 100-150 mg/dl higher than the normal fasting blood glucose.
3. Then, tumor-bearing mice are given 20% glucose intravenously by variable infusion and maintain plasma glucose concentrations at 300 mg/dl.
4. Blood samples are taken every 10 to 15 minutes to measure plasma glucose and insulin concentrations.

• The workflow of hyper-insulinemic euglycemic clamp assay as following:

1. The tumor-bearing mice need to fasten before performing the hyper insulinemic euglycemic clamp to prevent glucose changes caused by eating. The duration of fasting is determined based on preliminary experimental results.
2. After fasting, the tumor-bearing mice receive continuous insulin infusions. An initial dose that achieves high insulin levels is infused first.
3. A variable glucose infusion is then given.
4. The glucose infusion rate is determined by glucose measure results. The rate of glucose infusion reflected systemic insulin action in the tumor-bearing mice, with more glucose infusions indicating increased insulin action.
5. The combination of isotope tracers and hyperglycemic clamp experiments enables the assessment of insulin action in different parts of the tumor-bearing mice.

Deliverables

These assays provide an assessment of insulin secretion capacity, pancreatic function, and β cell function in awake tumor-bearing mice.

Applications

• The relationship between cancer and metabolic diseases such as diabetes.
• Toxicity assessment of metabolic pathway modulators.
• Isotope tracer injections can be combined with clamping techniques to assess differences in the ability of tumor tissues to take glucose uptake from normal tissues.
• We can optimize and improve glucose clamping technology.

CD BioGlyco provides hyperglycemic clamp and hyper-insulinemic euglycemic clamp assays services. Our experienced teams of scientists, researchers, and technicians provide fast turnaround, high-quality services at competitive prices for worldwide customers. Our customers have direct access to our staff and prompt feedback on their inquiries. If you are interested in our services, please contact us for more details.

Reference:

1. Gerst F, et al. The Expression of Aldolase B in Islets Is Negatively Associated With Insulin Secretion in Humans. J Clin Endocrinol Metab. 2018 Dec 1; 103(12): 4373-4383.