Research Techniques and Solutions
Make powerful conclusions with continuous, stress-free blood glucose data.

                



Glucose Tolerance Tests

An oral glucose tolerance test (OGTT) or intra-peritoneal glucose tolerance test (IPGTT) is used to assess the body’s ability to metabolize glucose.  In humans an OGTT is commonly used to diagnose type 2 diabetes.  In animal research the GTT is used to assess the degree of diabetes and also to test the desired effects of insulin or other drugs on the body’s ability to process glucose.  It can also be used to detect the unintended side-effects of drugs intended to treat other unrelated diseases.

Traditional methods of performing a GTT are manual and time-consuming. However, researchers can automate the process with Implantable telemetry with no need to collect manual measurements other than for (optional) reference purposes.  In addition, continuous data will provide improved resolution in amplitude and time-based parameters.

oral glucose tolerance test, what is a glucose tolerance test
what is a glucose tolerance test, intra-peritoneal glucose tolerance test, IPGTT



Type 1 Diabetes

As streptozotocin (STZ) selectively targets and kills pancreatic beta cells, it is widely used as an agent to induce Type 1 Diabetes Mellitus (T1DM).  STZ models of T1DM are used for assessing mechanisms, screening treatments, and evaluating therapeutic approaches directed at diabetic complications.

Implantable telemetry provides insights into the onset of this disease at a level not previously available, as shown in the plot below displaying the average and standard error measures across 11 rats.  Following dosing, as indicated by the arrow and STZ abbreviation, blood glucose values increase as the beta cells are shocked and stop producing insulin. As the beta cells die and release all of their insulin, blood glucose drops. Over the next day, blood glucose increases again as significantly less insulin is being produced. The animal then achieves a new hyperglycemic homeostasis.

STZ Induction, T1DM, t1dm

After induction, the use of implantable telemetry will similarly provide enhanced insights into effectiveness of managing diabetes through insulin treatments, comparisons of different drugs, and more.


Implantable telemetry will improve T1DM research by providing continuous data with improved resolution in amplitude and time-based parameters.




Insulin Dose Response

In general, a dose response study is used to establish a physiologic profile of the response to a bolus administration of a specific drug.  Studies will often compare multiple doses of the same drug or therapeutic doses of several drugs.  An insulin dose response study can be used to characterize the action of one or more insulin products to determine how quickly it reduces blood glucose levels and how long the effect lasts.  As with other drug classes, it is often interesting to compare one insulin product to another.

In the example below, two groups of six rats were given long acting insulin #1 or #2 for multiple days so that equilibrium could be achieved.  The dose response curves were then collected and analyzed.  Insulin #2 shows both longer reduction of hyperglycemia after dosing and an overall effect of lowered maximum glycemia indicating that if all other things are equal it may be a better option for T1DM treatment than Insulin #1.




Type 2 Diabetes

Approximately 90% of diabetes cases are type 2, driving strong interest in effective animal models.  Available models express various characteristics of diabetes including insulin resistance, reduced insulin production, leptin resistance, etc.

The example below shows data from 6 fa/fa rats.  The lean group of 3 rats were fed standard diet and the diabetic group of 3 rats were fed a high fat diet beginning two weeks prior to implantation.  This data illustrates both the surgical recovery of the rats and the progressive onset of type 2 diabetes (TD2M).

Continuous glucose telemetry may be used by T2DM researchers to provide continuous and chronic glucose data throughout their studies.  In acute studies, such as a GTT, this may lead to incremental sensitivity and insights for comparing groups of animals.  In chronic studies, it may allow for new insights into hyperglycemic variability at a level not previously possible.




Select References

Culler MD, Delale T, Milano S, van der Lely AJ, Abribat T, Clemmons D. (2019). "Impaired glucose homeostasis in leptin-deficient ob/ob mice is corrected by AZP-3404, a 9-amino acid peptide analog derived from insulin-like growth factor-binding protein 2, a key mediator of leptin action". Endocrine Abstracts, 63(OC6.1). https://doi.org/10.1530/endoabs.63.OC6.1

Golic M, Kraker K, Fischer C, Alenina N, Haase N, Herse F, Schutte T, Henrich W, Muller DN, Busjahn A, Bader M, Dechend R. (2018). "Continuous Blood Glucose Monitoring Reveals Enormous Circadian Variations in Pregnant Diabetic Rats". Frontiers in Endocrinology. https://doi.org/10.3389/fendo.2018.00271

Iuchi H, Sakamoto M, Matsutani D, Hirofumi S, Kayama Y, Takeda N, Minamisawa S, Utsunomiya K. (2017). "Time-dependent effects of ipragliflozin on behaviour and energy homeostasis in normal and type 2 diabetic rats: continuous glucose telemetry analysis". Scientific Reports, 7, https://doi.org/10.1038/s41598-017-12106-y

Korstanje R, Ryan JL, Savage HS, Lyons BL, Kane KG, Rizzo SJS. (2017). "Continuous Glucose Monitoring in Female NOD Mice Reveals Daily Rhythms and a Negative Correlation With Body Temperature". Endocrinology, 158(9). https://doi.org/10.1210/en.2017-00266

Martire VL, Valli A, Bingaman MJ, Zoccoli G, Silvani A, Swoap S. (2018). "Changes in blood glucose as a function of body temperature in laboratory mice: implications for daily torpor". Endocrinology and Metabolism, 315(4): E662-E670. https://doi.org/10.1152/ajpendo.00201.2018
 


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How could continuous glucose telemetry improve your research?

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