Greek hyperinsulinemic women, with or without polycystic ovary syndrome, display altered inositols metabolism

Abstract

BACKGROUND We have shown that American women with polycystic ovary syndrome (PCOS) have decreased glucose-stimulated release of a putative mediator of insulin action, D-chiro-inositol (DCI)-containing inositolphosphoglycan (DCI-IPG), and increased urinary clearance of DCI (uCl(DCI)), which was associated with hyperinsulinemia.

Methods: DCI levels and the release of insulin and DCI-IPG during an oral glucose tolerance test (AUCs) were assessed in 27 Greek PCOS and 10 normal Greek women.

Results: PCOS women were heavier than controls (BMI = 28.4 versus 23.7 kg/m(2), P = 0.05) with higher waist-to-hip ratios (WHR = 0.78 versus 0.71, P = 0.009) and increased free testosterone (P = 0.048) and AUC(insulin) (P = 0.04). In PCOS women, incremental AUC(DCI-IPG) was significantly decreased by 59% (2158 versus 5276%.min, P = 0.01), even after correction for BMI and WHR. Finally, increased uCl(DCI) (r = 0.35, P = 0.04) and decreased AUC(DCI-IPG) (r = 0.46, P = 0.004) were significantly associated with hyperinsulinemia in all women together, even after correction for BMI and WHR (Ps = 0.02 and 0.007), and regardless of PCOS status.

Conclusions: Greek women, with or without PCOS, display increased uCl(DCI) and decreased AUC(DCI-IPG) in association with higher insulin levels but independent of adiposity. Increased clearance of inositols might reduce tissue availability of DCI and decrease the release of DCI-IPG mediator, which could contribute to insulin resistance and compensatory hyperinsulinemia in Greek women, as previously described in American women.

Figures

Figure 1:

Correlations between glucose-stimulated insulin levels (AUCinsulin) and uClDCI (A) or glucose-stimulated DCI-containing inositolphosphoglycan (AUCDCI-IPG) bioactivity (B) in Greek women with PCOS (•) and Greek control women (○). After pooling data from this study and a previously published PCOS study (Baillargeon et al., 2006)), C and D illustrate correlations between AUCinsulin and uClDCI (C) or AUCDCI-IPG (D) in Greek PCOS (•) and control (○) women, as well as American PCOS (▪) and control (□) women. Results are represented back transformed in their original units, on log scales. ‡P = 0.02 or §P ≤ 0.007 when adjusted for BMI and WHR