Alterations in glucose metabolism during menstrual cycle in women with IDDM.

OBJECTIVE: To examine the hormonal mechanisms underlying the variability in glycemic control during the different phases of the menstrual cycle in women with insulin-dependent diabetes mellitus (IDDM). RESEARCH DESIGN AND METHODS: Hyperglycemic (11.7 +/- 0.1 mM), hyperinsulinemic (24 +/- 3 mU/L) clamp studies were performed in 16 women with IDDM during the follicular (day 8 +/- 1) and luteal (day 23 +/- 1) phases of the menstrual cycle. Seven of the patients (group 1) experienced worsening glucose control during the luteal phase, whereas nine patients (group 2) did not.
RESULTS: In group 1, glucose metabolism fell from 30.2 +/- 3.8 mumol.kg-1.min-1 during the follicular phase to 24.5 +/- 2.0 mumol.kg-1.min-1 during the luteal phase (P = 0.09), whereas in group 2 it increased from 18.5 +/- 1.2 to 23.2 +/- 2.3 mumol.kg-1.min-1 (P = 0.03). The decrease in glucose metabolism during the luteal phase in patients in group 1 was associated with a significant rise in the serum estradiol levels from the follicular to luteal phase (164 +/- 39 vs. 352 +/- 59 pM, P = 0.006), whereas this rise was not observed in group 2 (334 +/- 156 vs. 423 +/- 74 pM, NS). Changes in other reproductive hormones (progesterone, testosterone, dihydrotestosterone, androstenedione, luteinizing hormone, follicular-stimulating hormone, or prolactin) were not related to the differences in glucose uptake in the two groups.
CONCLUSIONS: 1) Marked heterogeneity in glucose metabolism is seen throughout the menstrual cycle in women with IDDM, 2) a subgroup of patients exhibits worsening premenstrual hyperglycemia and a decline in insulin sensitivity during the luteal phase, and 3) the deterioration in glucose uptake in this subgroup was associated with a greater increment in estradiol levels from the follicular to the luteal phase.