Goto, Takashi

Higaki, Yasuki

Kumagai, Shuzo

Sasaki, Haruka

The goal of this study was to evaluate the levels of insulin sensitivity, sex hormones and sex hormone-binding globulin (SHBG), and the relationship of insulin sensitivity with abdominal fat accumulation, sex hormones, and SHBG in Japanese men with impaired glucose tolerance (IGT). Insulin sensitivity (glucose infusion ratio; GIR) was evaluated by the hyperinsulinemic euglycemic clamp method, abdominal fat accumulation was determined by computed tomography, sex steroid hormones and SHBG were measured in 29 men with impaired glucose tolerance who ranged in age from 31 to 75 yrs. The participants in this study included both lean and obese subjects. The distribution of sex hormones were relatively similar to the ranges observed in healthy men based on the findings of our previous report, but the SHBG levels tended to be lower than those of healthy men. Among these subjects, about 50% were within the normal ranges for GIR. In a simple correlation analysis, GIR showed a significant positive correlation with age and SHBG, and a negative association with obesity indices, especially for subcutaneous fat area (SFA). A stepwise multiple regression analysis indicated that the SFA and area under the curve of insulin (AUCIRI) are independently associated with the GIR. Moreover, it is observed that neither SHBG and free testosterone were related to insulin action after taking into account for fat levels. Based on these findings, it is suggested that abdominal subcutaneous fat accumulation and hyperinsulinemic responses to oral glucose load were independent contributors of the peripheral insulin sensitivity in Japanese men with IGT.本研究の目的は、耐糖能境界型(IGT)男性の性ホルモン、性ホルモン結合グロブリン(SHBG)及びインスリン感受性の水準を比較検討すると共にインスリン感受性と性ホルモン及びSHBGとの関連性を明らかにすることである。Hyperinsulinemic euglycemic clamp法で評価したインスリン感受性(glucose infusion rate; GIR),CTスキャン法で評価された腹部の皮下(SFA)・内臓脂肪蓄積(VFA)，性ホルモン(遊離テストステロン，エストラディオール，dehydroepiandrosterone-sulfate)及びSHBG水準が，やせ型から肥満者を含む31-75歳の日本人男性IGT(n=29)を対象に測定された。性ホルモンの分布は，すでに著者らが報告した健常男性で観察された数値の範囲内にあった。しかしながら，統計処理は行っていないが，SHBG水準は健常者よりも低い傾向にあった。GIRに関しては，IGT男性の約50%が正常範囲内にあった。単相関分析において，GIRは年令やSHBGとの間に有意な正相関を，一方肥満尺度，特に腹部の皮下脂肪面積(SFA)との間に有意な負の相関を認めた。ステップワイズ重回帰分析の結果，SFAと75gの経口糖負荷試験(OGTT)に伴うインスリンの曲線下面積は，GIRに関する有意な独立因子であった。さらに，SHBGや遊離テストステロンは,OGTTに伴うインスリン反応と有意な負の相関を認めたが,腹部のSFA及びVFAの影響を考慮した偏相関分析の結果，両者の間には有意な関連性は認められなかった。これらの成績から，腹部の皮下脂肪蓄積や経口糖負荷後の高インスリン反応は，日本人IGT男性の末梢インスリン感受性の独立因子であることが示唆された

熊谷, 秋三

クマガイ, シュウゾウ

桧垣, 靖樹

ヒガキ, ヤスキ

佐々木, 悠

ササキ, ハルカ

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The Relationship of Insulin Sensitivity to Abdominal Fat Accumulation, Sex Hormones, and Sex Hormone-Binding Globulin in Japanese Men with Impaired Glucose Tolerance

The Relationship of Insulin Sensitivity to Abdominal Fat Accumulation, Sex Hormones, and Sex Hormone-Binding Globulin in Japanese Men with Impaired Glucose Tolerance

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