Insulin action during pregnancy. Studies with the euglycemic clamp technique

Area of Science:

• Endocrinology
• Metabolic Disorders
• Reproductive Physiology

Background:

• Insulin resistance is a hallmark of normal pregnancy and gestational diabetes.
• Understanding the underlying mechanisms is crucial for managing these conditions.

Purpose of the Study:

• To investigate the mechanisms of insulin resistance in normal pregnancy and gestational diabetes.
• To differentiate between insulin binding and post-binding defects in insulin action.

Main Methods:

• Euglycemic glucose clamp technique to measure exogenous glucose disposal.
• Erythrocyte insulin binding assays.
• Sequential insulin infusions at varying rates.

Main Results:

• Pregnant women, especially those with gestational diabetes, exhibited significant insulin resistance compared to nonpregnant controls.
• Insulin binding to erythrocytes was similar across all groups.
• Increased insulin infusion rates revealed a reduced insulin responsivity, indicating a post-receptor defect.
• Insulin resistance significantly improved postpartum.

Conclusions:

• Pregnancy-induced insulin resistance is characterized by a post-receptor defect in insulin action.
• Gestational diabetes exacerbates this insulin resistance.
• The defect is primarily related to insulin responsivity, not initial insulin binding.