Insulin resistance is an independent correlate of high serum levels of advanced glycation end products (AGEs) and low testosterone in non-diabetic men

Abstract

Advanced glycation end products (AGEs) are involved in cardiovascular disease. Low testosterone level is associated with increased risks of cardiometabolic disorders as well. However, which anthropometric and metabolic variables, including AGEs, are independently correlated with low testosterone is largely unknown. In this study, we investigated whether high serum level of AGEs is one of the independent determinants of low testosterone in non-diabetic men. One hundred thirteen non-diabetic men who did not receive any drugs for hypertension and dyslipidemia underwent a complete history and physical examination, determination of blood chemistries, including serum AGEs and testosterone. Univariate analysis showed that testosterone levels were associated with waist circumference (inversely), diastolic blood pressure (BP) (inversely), mean BP (inversely), triglycerides (inversely), HDL-cholesterol, fasting plasma glucose (inversely), fasting insulin (inversely), homeostasis model assessment of insulin resistance (HOMA-IR) (inversely), AGEs (inversely) and uric acid (inversely). By the use of multiple stepwise regression analyses, HOMA-IR (p = 0.005) and triglycerides levels (p < 0.05) remained significant and were independently related to testosterone levels (R(2) = 0.168). HOMA-IR index was one of the independent determinants of serum levels of AGEs as well. The present study demonstrated for the first time that HOMA-IR was independently associated with high serum levels of AGEs and low testosterone in non-diabetic men. Insulin resistance could link elevation of AGEs to testosterone deficiency in non-diabetic men.

Keywords: AGEs; insulin resistance; testosterone.

Figure 1

Inverse correlation between serum levels of testosterone and AGEs. serum levels of AGEs were inversely correlated with testosterone levels in our subjects. One hundred thirteen consecutive male outpatients in Kurume University Hospital with a mean age of 58.8 ± 8.5 years old were enrolled in the present study. Blood was drawn from the antecubital vein in the morning. Measurement of AGEs was performed with a competitive enzyme-linked immunosorbent assay (ELISA). In this study, one unit (U) corresponds to 1 µg of glyceraldehyde-derived AGE-bovine serum albumin standard. Serum testosterone level was measured with electro-chemiluminescence immunoassay.