The Gonadal Hormone Regulates the Plasma Lactate Levels in Type 2 Diabetes Treated With and Without Metformin

Abstract

Our previous study showed there was a gender difference in plasma lactate concentrations in subjects with type 2 diabetes. This study investigated the effect of sex hormone levels on plasma lactic acid (LA) levels in type 2 diabetes with and without metformin therapy. Fasting whole blood specimens of 392 type 2 diabetes patients treated with metformin (n=199) or not (n=193) were collected. LA was measured with an enzyme-electrode assay. Levels of sex hormones, including testosterone (T) and estradiol (E(2)), were measured with a chemiluminescence microparticle immunoassay. Spearman's or Pearson's correlation and logistic regression analysis were performed for the factors associated with LA. The LA level in the metformin group was significantly higher than that in the non-metformin group (1.26±0.43 vs. 1.14±0.49 mmol/L, P<0.001), and LA levels of females were significantly higher than those of males (P<0.001). LA concentrations were positively correlated with E(2) level but negatively correlated with metformin and T levels (P<0.01). The logistic regression analysis showed that gender, creatinine, E(2), metformin, and T were independent factors influencing lactate levels. Analysis of subgroups demonstrated that the LA concentrations increased with the elevation of E(2) level (P<0.05) but decreased with the rising of T level (P<0.05). Sex hormones play an important role on regulating plasma lactate levels in diabetes patients treated with metformin. E(2) up-regulates but T tend to down-regulate lactate levels.