Which hormonal changes contribute to the dawn phenomenon?

The dawn phenomenon is characterized by an increase in blood glucose levels that occurs in the early morning hours, typically between 2 a.m. and 8 a.m. One of the key hormonal changes that contributes to this phenomenon is the release of cortisol. Cortisol, a glucocorticoid hormone produced by the adrenal cortex, plays a significant role in glucose metabolism.

In the early morning, as part of the body’s natural circadian rhythm, there is an increase in cortisol production. This hormone promotes gluconeogenesis (the production of glucose from non-carbohydrate sources) in the liver, which results in increased glucose availability in the bloodstream. Additionally, cortisol has an antagonistic effect on insulin, meaning it can cause insulin resistance, further contributing to elevated blood glucose levels.

The other options do not play a significant role in the dawn phenomenon. For example, while insulin typically decreases blood glucose levels, its increase would not lead to the phenomenon. Similarly, a decrease in glucagon would lower blood glucose levels, which is opposite to what is observed during the dawn phenomenon. The increase in adrenaline (or epinephrine) may facilitate gluconeogenesis as well, but it is cortisol's specific influence during the early morning that is most notable in this