title: Fructose induces glucose-dependent insulinotropic polypeptide, glucagon-like peptide-1 and insulin secretion: Role of adenosine triphosphate-sensitive K(+) channels.
abstract: Adenosine triphosphate-sensitive K(+) (KATP) channels play an essential role in glucose-induced insulin secretion from pancreatic β-cells. It was recently reported that the KATP channel is also found in the enteroendocrine K-cells and L-cells that secrete glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), respectively. In the present study, we investigated the involvement of the KATP channel in fructose-induced GIP, GLP-1 and insulin secretion in mice. Fructose stimulated GIP secretion, but pretreatment with diazoxide, a KATP channel activator, did not affect fructose-induced GIP secretion under streptozotocin-induced hyperglycemic conditions. Fructose significantly stimulated insulin secretion in Kir6.2 (+/+) mice, but not in mice lacking KATP channels (Kir6.2 (-/-) ), and fructose stimulated GLP-1 secretion in both Kir6.2 (+/+) mice and Kir6.2 (-/-) mice under the normoglycemic condition. In addition, diazoxide completely blocked fructose-induced insulin secretion in Kir6.2 (+/+) mice and in MIN6-K8 β-cells. These results show that fructose-induced GIP and GLP-1 secretion is KATP channel-independent and that fructose-induced insulin secretion is KATP channel-dependent.
authors.affiliation: Department of Metabolic Medicine, Nagoya University Graduate School of Medicine Nagoya, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Seino
authors.affiliation: Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine Nagoya, Japan.
authors.forename: Hidetada
authors.initials: H
authors.lastname: Ogata
authors.affiliation: Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine Nagoya, Japan.
authors.forename: Ryuya
authors.initials: R
authors.lastname: Maekawa
authors.affiliation: Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine Nagoya, Japan.
authors.forename: Takako
authors.initials: T
authors.lastname: Izumoto
authors.affiliation: Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine Nagoya, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Iida
authors.affiliation: Department of Diabetes, Endocrinology and Nutrition, Graduate School of Medicine, Kyoto University Kyoto, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Harada
authors.affiliation: Department of Medical Physiology, Graduate School of Medicine, Chiba University Chiba, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Miki
authors.affiliation: Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine Kobe, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Seino
authors.affiliation: Department of Diabetes, Endocrinology and Nutrition, Graduate School of Medicine, Kyoto University Kyoto, Japan.
authors.forename: Nobuya
authors.initials: N
authors.lastname: Inagaki
authors.affiliation: Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine Nagoya, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Tsunekawa
authors.affiliation: Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine Nagoya, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Oiso
authors.affiliation: Department of Metabolic Medicine, Nagoya University Graduate School of Medicine Nagoya, Japan.
authors.forename: Yoji
authors.initials: Y
authors.lastname: Hamada
keywords: Adenosine triphosphate-sensitive K+ channe; Fructose; Hormone secretion