Byetta increases blood sugar during exericse

November 10, 6:09 PMDiabetes ExaminerRobert Scheinman

Previous

Comment Print Email RSS Subscribe

Subscribe

Get alerts when there is a new article from the Diabetes Examiner. Read Examiner.com's terms of use.

Email Address   Include other special offers from Examiner.com Terms of Use

Byetta is a drug which stimulates insulin secretion while suppressing glucagon secretion. It works by stimulating a receptor found on cells of the pancreas. During exercise insulin levels fall and glucagon levels rise as the need for mobilizing stored glucose increases to feed hungry muscles. It stands to reason that if one took Byetta, they would be more likely to experience hypoglycemia while exercising than someone not taking the drug. To establish whether this was indeed true, a British research group led by Dr. Peter Mansell set about studying the effects of Byetta on healthy volunteers during exercise. The results, published this week in Diabetologia were quite surprising.

The study was performed on 8 healthy males averaging 35 years of age with a body mass index of approximately 25. It was designed as a double blind crossover experiment which means that neither the participants nor the researchers knew who received the drug or the placebo until after the experiment. It was a crossover study in that the control group and the drug group switched places for the second trial so that researchers had data for both conditions on all participants. The participants fasted overnight and in the morning received a dose of either Byetta or placebo. They rested for 105 minutes (the average time to peak serum concentrations for the drug) and then cycled for 75 minutes. During the exercise period they were monitored for intensity. The particpants then rested again. Blood was taken at various points during this process.

What the blood analysis revealed was that Byetta actually caused blood sugar to increase during exercise rather than decrease. No hypoglycemia occurred. Since the researchers had the blood samples, they were able to do further tests. They looked at serum cortisol levels as well as adrenaline levels. Both were significantly higher during the exercise phase in the Byetta group as compared to the control group. This most likely provides an explanation for the effect. Both cortisol and adrenaline promote the mobilization of glucose as they are part of the stress and the flight or fight response respectively. While stress induced increases in blood sugar is bad most of the time as it contributes to the diabetic’s blood glucose load, during exercise it is a very good thing as this is the time at which hypoglycemia is likely to occur.

The one caveat to these conclusions in so far as diabetes is concerned is that they were generated by observing healthy people. It remains to be seen if exercising diabetic people show the same physiological response.

It probably seemed a bit foolish to initiate this experiment. Many would have said “Of course you will see hypoglycemia in the Byetta treated group – why even bother?” Sometimes the results are as expected and everyone wonders – why did you bother? Sometimes, however, we get these sorts of results. If we don’t do the experiment we will never know the truth.

If you are interested in reading more about the science of diabetes or are interested in uplifitng and informative articles, recipes, and blogs about diabetes; try A Sweet Life, the magazine for the healthy diabetic. http://asweetlife.org