Insulin Resistance Is an Intrinsic Defect Independent of Fat Mass in Women with Turner’s Syndrome

Abstract

Background/Aims: Turner’s syndrome (TS) is associated with increased insulin resistance and adiposity, which might be associated with type 2 diabetes in later life. We aimed to determine whether the defect in insulin sensitivity is a primary intrinsic defect in TS or dependent on variation in body composition. Methods: Sixteen women with TS not on growth hormone replacement but receiving oestrogen replacement therapy [age (mean ± SD): 30.2 ± 8.5 years; height-corrected fat-free mass: 26.1 ± 3.1 kg/height] and a control group of 16 normal healthy women (age: 30.1 ± 8.2 years; height-corrected fat-free mass: 25.9 ± 2.4 kg/height) were studied. Fasting blood samples were obtained for measurement of glucose, insulin, IGF-I, IGFBP-1, IGFBP-3 and lipid levels. The hyperinsulinaemic euglycaemic clamp was performed to assess peripheral insulin sensitivity (M value), and the Homeostasis Model Assessment (HOMA-S) was used to estimate fasting insulin sensitivity. Body composition was assessed using a dual-energy X-ray absorptiometry scan. Results: Fasting insulin sensitivity (HOMA-S 103.2 ± 78.6 vs. 193.9 ± 93.5, p = 0.006) was lower in TS subjects compared to controls as was whole-body insulin sensitivity (M value 2.9 ± 1.9 vs. 5.5 ± 2.6 mg/kg/min, p = 0.003). In a multiple regression analysis the Turner karyotype was significantly related to insulin sensitivity (p = 0.008) independent of any differences in fat-free mass and percent whole-body fat mass. Conclusion: The increased insulin resistance in women with TS is independent of measures of body composition and may represent an intrinsic defect related to their chromosomal abnormality.

Skeletal Muscle Abnormalities in Girls and Adolescents With Turner Syndrome

“…This is the first study to examine the complex relationship between exercise and metabolic function in TS using 31 P-MRS and demonstrates that participants with TS experience a difference in the metabolic demands of exercise compared with girls without TS. It has been well documented that women with TS exhibit many characteristics of the metabolic syndrome: insulin resistance, increased central adiposity with elevated visceral fat stores, and hypertension (9,33,34). These symptoms are known to impair exercise performance, and indeed, metabolic syndrome has also been associated with defects in oxidative phosphorylation.…”

Long-Term Follow-Up of GH-Treated Girls with Turner Syndrome: Metabolic Consequences

“…However, because untreated young TS women have been reported to have a higher prevalence of insulin resistance and impaired glucose tolerance [19], we believe this phenomenon may also be related to TS. Salgin et al [20] recently presented data on the insulin and glucose levels in untreated TS women aged 29.9 (16.5–46.6) years. They showed an insulin sensitivity of 103 ± 78.6%, which is not significantly different compared to 81.6 ± 46.5% in our GH-treated TS women aged 20.0 ± 2.1 years.…”

Hypoglycemic Efficacy of Catharanthus roseus and Opuntia ficusindica in Mice Diabetic Model

“…Bakalov et al, (2009) have investigated that Turner syndrome (TS) is caused by the absence or fragmentation of the second sex chromosome, which is associated with increased risk of diabetes mellitus (DM), but the specific phenotype and genetic etiology of this trait are unknown. Cytogenetic factors related with diabetes have been largely reviewed by Bakalov et al, (2004), Salgin et al, (2006), Song et al, (2008), Neve et al, (2005), Snee et al, (2006), Zhao et al, (2005), Mokhtari et al, (2008) etc. Suheir Assady (2009) has suggested the stem cell based therapy of diabetes mellitus.…”