Hyperinsulinemia is closely related to low urinary clearance of D-chiro-inositol in men with a wide range of insulin sensitivity.
ABSTRACT We have previously shown that women with polycystic ovary syndrome (PCOS) have increased urinary clearance of D-chiro-inositol (uCl(DCI)), which was positively associated with hyperinsulinemia. The objective of this study was thus to determine if such relationship also exists in men with a large range of insulin sensitivity and levels. A cross-sectional study was performed on 11 brothers of women with PCOS and 21 control men. In this study, brothers served as a model of insulin resistance. We assessed uCl(DCI), urinary clearance of myo-inositol, and insulin levels with a standard 75-g oral glucose tolerance test, a 2-hour euglycemic-hyperinsulinemic clamp, and a 24-hour urine collection. Our results showed in all men together that low uCl(DCI) was strongly associated (P < .001) with hyperinsulinemia, for which uCl(DCI) was a significant predictor independent of other classic factors. Brothers were heavier than controls (P = .02), with increased glucose-stimulated glucose (P < .001) and insulin levels (P < .001) and reduced insulin sensitivity (P = .001). In this group, plasma DCI was increased by 3-fold (P = .02), with a 3-fold decrease in the uCl(DCI) to urinary clearance of myo-inositol ratio, which was almost significant (P = .07). Low uCl(DCI) is strongly associated with hyperinsulinemia in all men, and brothers of PCOS women who are more insulin resistant display increased plasma DCI and borderline decreased uCl(DCI). Thus, compensatory hyperinsulinemia might suppress renal clearance of DCI to increase plasma DCI levels and partially compensate for insulin resistance by improving DCI availability in men. The apparent discrepancy with PCOS women might be explained by higher insulin levels in men as compared with women and requires confirmation.
- Diabetes Care 02/1996; 19(1):76-8. · 7.74 Impact Factor
- Journal of Clinical Endocrinology & Metabolism 05/1994; 78(4):810-5. · 6.43 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: The urinary excretions of myo-inositol and D-chiro-inositol are elevated in diabetes, and have been suggested as possible markers or effectors of insulin action. The aim of the present study was to measure the urinary excretion of these compounds, and to assess possible relationships with the metabolic control of glucose, in older, non-diabetic men and women. 32 older (age range 54-71 yrs), moderately overweight (body mass index 29.1 +/- 0.4 kg/m2, mean +/- SEM), non-diabetic men (n = 17) and women (n = 15). 75 g oral glucose tolerance testing was done the day after all subjects had consumed nutrient-defined menus for five days. Plasma samples were analyzed for the concentrations of glucose, insulin, and C-peptide, and the 180-minute area under the curve (AUC) for each of these compounds was calculated. Samples from 24-hour urine collections were analyzed for the concentrations of myo-inositol, D-chiro-inositol, L-chiro-inositol, and pinitol. The fasting glucose, insulin, and C-peptide, and the AUC for glucose and insulin, were not different between men and women. C-peptide AUC was greater in the men versus the women (p < 0.001). The median urinary excretions (micromol/g creatinine) of myo-inositol (p < 0.001), D-chiro-inositol (p < 0.001), L-chiro-inositol (p < 0.05), and pinitol (p < 0.001) were higher, and the myo-inositol:D-chiro-inositol ratio was lower (p < 0.001), in the men versus women. For all subjects combined, C-peptide AUC was positively correlated with the urinary excretion of each of the measured inositols, as well as the myo-inositol:D-chiro-inositol ratio. The correlations between C-peptide AUC and these inositols were strongly influenced by the co-linear relationship between C-peptide AUC and gender. Collectively, these data show that older, moderately overweight, non-diabetic men and women with gender-related differences in glucose-stimulated C-peptide AUC, an indirect indicator of insulin secretion, also display differences in the urinary excretion of myo-inositol, D-chiro-inositol, L-chiro-inositol, and pinitol. The gender-related difference in the myo-inositol:D-chiro-inositol ratio suggests that, while the urinary excretion of all of the inositols measured were higher in the men than the women, the difference was more pronounced for D-chiro-inositol.Hormone and Metabolic Research 01/2001; 33(1):44-51. · 2.15 Impact Factor