Changes in Insulin Sensitivity, Secretion and Glucose Effectiveness During Menstrual Cycle

Background l clinical conditions suggest an effect of sex steroids on glucose homeostasis in women. Studies examining this phenomenon have yielded controversial results. s estigate the effect of the menstrual cycle on insulin sensitivity, glucose effectiveness and acute insulin response to glucose using the tolbutamide-modified intravenous glucose tolerance test (IVGTT) during the follicular (day 8 ± 1) and luteal (day 23 ± 1) phases of the menstrual cycle, the authors recruited 12 healthy regularly menstruating women. All had fasting glucose concentration of <100 μg/dl ( 89.7 ± 6.2) with no family history of diabetes mellitus; their body mass indices were <25 kg/m2 (22.41 ± 1.44 kg/m2). s an insulin sensitivity (Si) values decreased during the cycle. Insulin sensitivity (Si × 10−4/min.mU/ml) was higher in the follicular phase (5.03 ± 0.72) and decreased in the luteal phase (2.22 ± 0.45) (p <0.001). Glucose effectiveness (Sg min−1) did not change as a function of the phase of the menstrual cycle. Sg estimates were 0.0229 ± 0.00323 in the follicular phase, and 0.0225 ± 0.00319 (p = NS) in the luteal phase, respectively. Acute insulin response (AIRg mU/ml) was 276.4 ± 27.8 in the follicular phase. An adaptive increase (304.4 ± 51.1) in response to the insulin resistance during the luteal phase was observed, but this increase was not statistically significant (p = NS). sions dge of the variations in insulin sensitivity that occur during the normal menstrual cycle provides a basis of comparison for studies of other clinical conditions. Also, this phenomenon should be considered if the determination of insulin resistance is the purpose of certain epidemiological studies.