Contrasting Testosterone Concentrations in Type 1 and Type 2 Diabetes

Abstract

We have recently reported (1) that male patients with type 2 diabetes have frequent hypogonadotrophic hypogonadism. We have now asked whether a similar defect may be observed in type 1 diabetic males to determine whether diabetes per se is the cause of hypogonadotrophic hypogonadism. RESEARCH DESIGN ANDMETHODS -Fifty patients with type 1 diabetes (age range 23-58 years) and 50 age-matched patients with type 2 diabetes (age range 28 -51 years) were included in the study. Patients with known history of hypogonadism, panhypopituitarism, or chronic debilitating disease such as renal failure, cirrhosis, or HIV infection were excluded from the study. Fasting blood samples were obtained from the patients, and total testosterone (TT), free testosterone (FT), sex hormone-binding globulin (SHBG), leutinizing hormone (LH), and follicle-stimulating hormone (FSH) were measured as previously described (1). FT and bioavailable testosterone (bioT) were calculated from SHBG and TT as previously described (1). Hypogonadism was defined as low FT or low calculated FT (2). Mann-Whitney rank-sum test or Student's t test for unpaired data, 2 test, and Spearman's test were used as appropriate (Sigmastat software).RESULTS -The mean TT, FT, calculated FT, and bioT concentrations in type 1 diabetic patients were in the middle of the normal range (Table 1). No patient had subnormal TT concentrations; three patients had supranormal TT, while two patients had subnormal FT and bioT concentrations.The mean TT concentration in patients with type 2 diabetes was significantly lower than that in type 1 diabetic subjects ( Table 1). The prevalence of low TT concentrations was 24 of 50 (48%), while that of low measured and/or calculated FT was 13 of 50 (26%). LH and FSH concentrations in 12 of 13 hypogonadal patients were in the normal range, and were thus inappropriately low. One patient had elevated LH and FSH concentrations and thus had primary hypogonadism. The mean prolactin concentration was lower in type 2 than in type 1 diabetic subjects.The mean SHBG concentration in type 1 diabetic subjects was at the upper end of the reference range. The level of SHBG was higher than normal in 16 patients. The mean SHBG in type 2 diabetic subjects was significantly lower than that in type 1 diabetic subjects (Table 1).In type 1 diabetic subjects, plasma TT concentrations were negatively related to BMI (r ϭ Ϫ0.52, P Ͻ 0.001), as were FT (r ϭ Ϫ0.36, P Ͻ 0.05), calculated FT (r ϭ Ϫ0.36, P Ͻ 0.05), and bioT (r ϭ Ϫ0.36, P Ͻ 0.05). In type 2 diabetic subjects, BMI was also negatively related to FT (r ϭ Ϫ0.55, P Ͻ 0.01), calculated FT (r ϭ Ϫ0.42, P Ͻ 0.05), bioT (r ϭ Ϫ0.45, P ϭ 0.01), and TT (r ϭ Ϫ0.382, P Ͻ 0.01) (Fig. 1). BMI was also inversely related to SHBG (r ϭ Ϫ0.34, P Ͻ 0.05). Plasma FSH concentrations were positively related to age (r ϭ 0.39, P ϭ 0.01) and to LH concentrations (r ϭ 0.38, P ϭ 0.01). In type 2 diabetic subjects, FSH was positively related to age (r ϭ 0.504, P Ͻ 0.01) and LH (r ϭ 0.454, P Ͻ 0.01). The total insulin dose and insulin dose pe...

Intensive insulin therapy increases sex hormone-binding globulin in newly diagnosed type 2 diabetic patients

“…However, a few studies have reported that serum SHBG concentrations are also inversely correlated with HbA1c and FPG in both men and women without diabetes (13,15,26), suggesting a relationship between SHBG and glucose homeostasis before the development of diabetes. However, we did not find such a relationship in patients with T2D in this study, which is consistent with the finding of no correlation between blood glucose and HbA1c with serum SHBG in type 1 diabetes (T1D) patients (27). One possible explanation is that in nondiabetic subjects, HbA1c and FPG may be proportionate to the index of insulin resistance whereas the relationship is lost in the state of diabetes.…”

Hypogonadotrophic Hypogonadism in Type 2 Diabetes, Obesity and the Metabolic Syndrome

“…We compared the prevalence of hypogonadism in age matched (mean age 43 years) T1D and T2D men. 6% of T1D mean were hypogonadal as compared to 26% of T2D men [12]. SHBG in T1D was higher than that in T2D men.…”

“…In addition, type 1 diabetes (T1D) is not commonly associated with HH [12]. Thus, clearly HH is a feature related to obesity, insulin resistance and T2D rather than hyperglycemia per se.…”

Gender differences in sclerostin and clinical characteristics in type 1 diabetes mellitus

“…hormones were reported previously in T1DM (27,28,29). Although the recruited subjects did not exhibit any clinical sign of hypogonadism or other hormonal disorders, however, we cannot rule out biochemical hormonal abnormalities having not looked at circulating sex hormones.…”

“…A reduced bone formation as a consequence of reduced osteoblast activity has been identified as the mean pathogenetic effect or for low bone mineral density (BMD) in subjects with T1DM (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39). intimal thickening in atherosclerosis, and Wnt/b-catenin signaling is a regulator of VSMC behavior (9).…”