Ajay Chaudhuri

Type 2 diabetes is associated with lower total testosterone (T) levels in cross-sectional studies. However, it is not known whether the defect is primary or secondary. We investigated the prevalence of hypogonadism in type 2 diabetes by measuring serum total T, free T (FT), SHBG, LH, FSH, and prolactin (PRL) in 103 type 2 diabetes patients. FT was measured by equilibrium dialysis. FT was also calculated by using T and SHBG (cFT). Hypogonadism was defined as low FT or cFT. The mean age was 54.7 +/- 1.1 yr, mean body mass index (BMI) was 33.4 +/- 0.8 kg/m(2), and mean HbA1c was 8.4 +/- 0.2%. The mean T was 12.19 +/- 0.50 nmol/liter (351.7 +/- 14.4 ng/dl), SHBG was 27.89 +/- 1.65 nmol/liter, and FT was 0.250 +/- 0.014 nmol/liter. Thirty-three percent of patients were hypogonadal. LH and FSH levels were significantly lower in the hypogonadal group compared with patients with normal FT levels (3.15 +/- 0.26 vs. 3.91 +/- 0.24 mIU/ml for LH and 4.25 +/- 0.45 vs. 5.53 +/- 0.40 mIU/ml for FSH; P < 0.05). There was a significant inverse correlation of BMI with FT (r = -0.382; P < 0.01) and T (r = -0.327; P < 0.01). SHBG correlated inversely with BMI (r = -0.267; P < 0.05) but positively with age (r = 0.538; P < 0.001) and T (r = 0.574; P < 0.001). FT correlated strongly with cFT (r = 0.919; P < 0.001) but not with SHBG. LH levels correlated positively with FT (r = 0.287; P < 0.05). We conclude that hypogonadotropic hypogonadism occurs commonly in type 2 diabetes.

OBJECTIVE: To compare the effect of a high-fat, high-carbohydrate meal (HFHC) with that of a high-fiber and fruit meal on the concentrations of endotoxin (lipopolysaccharide [LPS]), LPS-binding protein (LBP), the expression of toll-like receptors (TLRs), and the suppressor of cytokine signaling-3 (SOCS-3) in mononuclear cells. RESEARCH DESIGN AND METHODS: Healthy lean subjects were given 910 calories of either an HFHC meal (n = 10) or an American Heart Association (AHA)-recommended meal rich in fiber and fruit (n = 10) after an overnight fast. Blood was collected before and at 1, 2, and 3 h after the meal. Cellular indexes of oxidative and inflammatory stress; the expression of SOCS-3, TLR2, and TLR4 in mononuclear cells; and plasma concentrations of LPS and LBP were measured. RESULTS: HFHC meal intake induced an increase in plasma LPS concentration and the expression of SOCS-3, TLR2, and TLR4 protein, reactive oxygen species generation, and nuclear factor-kappaB binding activity (P < 0.05 for all). These increases were totally absent after the AHA meal rich in fiber and fruit. CONCLUSIONS: The novel changes described after the HFHC meal elucidate further the mechanisms underlying postprandial inflammation and also provide the first evidence explaining the pathogenesis of insulin and leptin resistance mediated by SOCS-3 after such meals. In contrast, an AHA meal does not induce these effects.

OBJECTIVE To determine the prevalence of subnormal testosterone concentrations in patients with obesity and with type 2 diabetes in a primary care clinic population. RESEARCH DESIGN AND METHODS Free testosterone concentrations of 1,849 men (1,451 nondiabetic and 398 diabetic) in the Hypogonadism In Males (HIM) study were analyzed. The HIM study was a U.S.-based cross-sectional study designed to define the prevalence of hypogonadism in men aged &amp;gt;45 years. Free testosterone was measured by equilibrium dialysis. RESULTS The prevalence of subnormal free testosterone concentrations in lean, overweight, and obese nondiabetic men was 26% (n = 275), 29% (n = 687), and 40% (n = 489), respectively (P &amp;lt; 0.001 for trend), and 44% (n = 36), 44% (n = 135), and 50% (n = 227), respectively, in diabetic men (P = 0.46 for trend within group and P &amp;lt; 0.05 compared with nondiabetic men). The mean free testosterone concentration of diabetic men was significantly lower than that of nondiabetic men. Free testosterone concentrations were negatively and significantly (P &amp;lt; 0.001) related to age (r = −0.37), BMI (r = −0.18), and sex hormone–binding globulin (r = −0.11) in multiple regression analysis. The average decline of free testosterone concentrations was 7.8 pg/ml per decade in nondiabetic men and 8.4 pg/ml per decade in diabetic men. CONCLUSIONS Forty percent of obese nondiabetic men and 50% of obese diabetic men aged ≥45 years have subnormal free testosterone concentrations. In view of its high prevalence, obesity is probably the condition most frequently associated with subnormal free testosterone concentrations in males. The concomitant presence of diabetes is associated with an additional increase in the prevalence of subnormal free testosterone concentrations.

OBJECTIVE: One-third of men with type 2 diabetes have hypogonadotropic hypogonadism (HH). We conducted a randomized placebo-controlled trial to evaluate the effect of testosterone replacement on insulin resistance in men with type 2 diabetes and HH. RESEARCH DESIGN AND METHODS: A total of 94 men with type 2 diabetes were recruited into the study; 50 men were eugonadal, while 44 men had HH. Insulin sensitivity was calculated from the glucose infusion rate (GIR) during hyperinsulinemic-euglycemic clamp. Lean body mass and fat mass were measured by DEXA and MRI. Subcutaneous fat samples were taken to assess insulin signaling genes. Men with HH were randomized to receive intramuscular testosterone (250 mg) or placebo (1 mL saline) every 2 weeks for 24 weeks. RESULTS: Men with HH had higher subcutaneous and visceral fat mass than eugonadal men. GIR was 36% lower in men with HH. GIR increased by 32% after 24 weeks of testosterone therapy but did not change after placebo (P = 0.03 for comparison). There was a decrease in subcutaneous fat mass (-3.3 kg) and increase in lean mass (3.4 kg) after testosterone treatment (P < 0.01) compared with placebo. Visceral and hepatic fat did not change. The expression of insulin signaling genes (IR-β, IRS-1, AKT-2, and GLUT4) in adipose tissue was significantly lower in men with HH and was upregulated after testosterone treatment. Testosterone treatment also caused a significant fall in circulating concentrations of free fatty acids, C-reactive protein, interleukin-1β, tumor necrosis factor-α, and leptin (P < 0.05 for all). CONCLUSIONS: Testosterone treatment in men with type 2 diabetes and HH increases insulin sensitivity, increases lean mass, and decreases subcutaneous fat.