Impaired glucose tolerance (IGT) is not associated with disturbed homocysteine metabolism

Elevated plasma total homocysteine (tHcy) has been suggested to be an addit ional risk factor for cardiovascular disease in subjects with impaired gluc ose tolerance (IGT) and Type 2 diabetes (T2D). In order to investigate whet her an insulin resistant/chronic hyperinsulinemic situation in male diabeti c and prediabetic subjects directly influences the tHcy metabolism, fasting tHcy and post-methionine load tHcy plasma levels (PML-tHcy) were determine d in 15 men with IGT, 13 men with newly diagnosed T2D, and 16 normoglycemic controls (NGT). Fasting tHcy (IGT, 13.1 +/- 4.6; T2D, 12.5 +/- 4.0; NGT, 1 0.7 +/- 4.4 mu mol/L) and PML-tHcy (IGT, 46.5 +/- 17.39; T2D1 41.1 +/- 6.8; NGT, 38.0 +/- 9.7 mu mol/L) showed no differences between the groups. East ing tHcy and PML-tHcy correlated with fasting proinsulin (r = 0.395, p < 0. 05; r = 0.386, p < 0.05) and creatinine (r = 0.489, p < 0.01: r = 0.339, p < 0.05), resp. Multiple regression analysis showed only a relationship betw een fasting tHcy and creatinine. No relationships have been found between f asting tHcy and PML-tHcy, resp., and indicators of an insulin resistant sta te, e.g., insulin and proinsulin, as well as serum cobalamin and folate con centrations. In conclusion, our data suggest that the degree of glucose int olerance has no direct impact on the metabolism of homocysteine. However, t Hcy levels tend to be elevated with the development of nephropathy, indicat ing an association between tHcy and renal function in these subjects.