Impaired HPA Responses to Hypoglycemia in Diabetes and Insulin Treatment's Limited Restoration

What is it about?

In a study on rats, it was found that diabetes led to increased basal activation of the hypothalamic-pituitary-adrenal (HPA) axis, as well as changes in the expression of certain genes related to the HPA axis. Despite this, the HPA response to hypoglycemia was markedly reduced in uncontrolled diabetes. Insulin treatment restored the HPA response to hypoglycemia but not the epinephrine response, which is an important counterregulatory hormone during severe hypoglycemia. The study also found that the defect in the corticotropin-releasing hormone (CRH) response could be related to the defective glucocorticoid receptor (GR1) response.

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Why is it important?

The study is important because it provides insights into the central mechanisms of the hypothalamic-pituitary-adrenal (HPA) response to hypoglycemia in diabetes. Despite increased basal HPA activity, HPA responses to hypoglycemia were markedly reduced in uncontrolled diabetes. The study also found that insulin treatment restored the HPA response to hypoglycemia but did not restore the deficient epinephrine response, which is an important counterregulatory hormone during severe hypoglycemia. Key Takeaways: 1. Increased basal HPA activity in diabetes does not restore HPA responses to hypoglycemia. 2. Insulin treatment restores HPA responses to hypoglycemia but does not restore the deficient epinephrine response. 3. Hypoglycemia decreased hippocampal GR1 mRNA expression in control and insulin-treated diabetic rats but not in diabetic rats. 4. The defect in CRH response could be related to the defective GR1 response.