title: Impaired beta-cell function and insulin sensitivity in Japanese subjects with normal glucose tolerance.
abstract: The development of type 2 diabetes mellitus is characterized by both impaired beta-cell function and increasing insulin resistance. To clarify the roles of them in developing type 2 diabetes, we evaluated insulin resistance by HOMA-IR and insulin secretion by HOMA beta-cell in 453 Japanese subjects whose fasting plasma glucose (FPG) and HbA(1c) levels were within normal range. HOMA beta-cell was found to decrease in the over 30 years groups, while HOMA-IR increased with body mass index (BMI). To analyze the reserve capacity of insulin secretion and insulin sensitivity, the 67 of them, who underwent a standard oral glucose tolerance test and were diagnosed with normal glucose tolerance (NGT), were divided into four degrees of BMI age-adjusted to 50 years. They were compared for insulinogenic index and ISI composite proposed by Matsuda and DeFronzo across the range of BMI. ISI composite was significantly less in the highest BMI group, while insulin secretion did not increase in the higher BMI groups. The subjects with higher BMI had remarkably lower insulinogenic indices than those with lower BMI. These data suggest that insulin secretory reserve is insufficient to compensate for increased insulin resistance in Japanese people with NGT at about 50 years of age.
authors.affiliation: Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kuroe
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Fukushima
authors.forename: Masaru
authors.initials: M
authors.lastname: Usami
authors.forename: Masaki
authors.initials: M
authors.lastname: Ikeda
authors.forename: Yoshikatsu
authors.initials: Y
authors.lastname: Nakai
authors.forename: Ataru
authors.initials: A
authors.lastname: Taniguchi
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Matsuura
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Suzuki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kurose
authors.forename: Koichiro
authors.initials: K
authors.lastname: Yasuda
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Yamada
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Seino
mesh_terms: D000328:Adult; D044466:Asian People; D001786:Blood Glucose / Q000032:analysis; D015992:Body Mass Index; D005215:Fasting / Q000097:blood; D005947:Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test; D006706:Homeostasis; D006801:Humans; D007333:Insulin Resistance; D007515:Islets of Langerhans / Q000473:pathology / Q000503:physiopathology*; D007564:Japan; D008875:Middle Aged
chemical_list: D001786:Blood Glucose; D005947:Glucose