Menstrual cycle phase may affect insulin sensitivity

A recent study published in nature matabolism provides new evidence of how brain insulin action can influence insulin sensitivity and its implications on women’s health, with a particular focus on the menstrual cycle.

A total of eleven women took part in the study, undergoing four hyperinsulinaemic-euglycaemic clamps - two in the follicular phase of the menstrual cycle and two in the luteal phase. Insulin action in the brain was introduced by the use of a nasal insulin spray, which was compared to a placebo spray in a crossover design. The primary endpoint of the study was the change in glucose infusion rate.

The results showed that administration of nasal insulin during the follicular phase resulted in a significant increase in the amount of glucose required to maintain euglycaemia compared with the placebo. In contrast, during the luteal phase of the female cycle, the effect of brain insulin had no influence on the glucose infusion rate.

In addition to the glucose infusion rate results, brain insulin sensitivity was assessed in 15 other women using functional magnetic resonance imaging and intranasal insulin administration. The result showed that the sensitivity of the hypothalamus was affected by insulin in the follicular phase but not in the luteal phase.

The study thus highlights that brain insulin action plays a critical role in improving peripheral insulin sensitivity in women, particularly during the follicular phase of the menstrual cycle. This suggests that brain insulin resistance may contribute to whole body insulin resistance in the luteal phase of the menstrual cycle.

For more information, please refer to the full paper published in nature metabolism.

Link to the paper

A press tagesschau release on the publication can be found here.