1414-P: Prolactin as a Potential Modulator for the Adaption to Insulin Resistance in Pregnancy

Aims: Plasma prolactin levels are associated with insulin sensitivity and diabetes in an age dependent manner. Pregnancy is a state of physiologically high prolactin concentrations and insulin resistance. Only when beta cells fail to compensate by producing sufficient amounts of insulin, gestational diabetes mellitus (GDM) develops. We aimed to elucidate the relationship of prolactin levels, insulin sensitivity, and the incidence of GDM in pregnancy.

Material and Methods: 321 women from the German Gestational Diabetes study were phenotyped with 5-point 75 g oral glucose tolerance tests during gestational weeks 27.1 ± 2.1 and repeatedly 1 to 10 years after delivery. Prolactin was measured in fasting state.

Results: GDM was diagnosed in 29%. During pregnancy, physiologically high prolactin levels associated negatively with insulin sensitivity. By contrast, prolactin was positively associated with insulin sensitivity after delivery (p_interaction < 0.0001). Despite prolactin’s association with impaired insulin sensitivity in pregnancy, higher prolactin levels were neither associated with AUC-glucose_0-120 nor GDM incidence (p>0.14). Prolactin interacted with AUC-glucose_0-120 on insulin secretion (disposition index, p=0.01) with higher prolactin levels associating with improved insulin secretion in case of AUC-glucose_0-120 above median (p=0.04).

Conclusion: Our findings on countercurrent changes in insulin sensitivity and secretion with higher prolactin levels could indicate a role for this hormone in mounting and compensating for physiologic insulin resistance in pregnant women.