title: Testosterone stimulates glucose uptake and GLUT4 translocation through LKB1/AMPK signaling in 3T3-L1 adipocytes.
abstract: Decreases in serum testosterone concentrations in aging men are associated with metabolic disorders. Testosterone has been reported to increase GLUT4-dependent glucose uptake in skeletal muscle cells and cardiomyocytes. However, studies on glucose uptake occurring in response to testosterone stimulation in adipocytes are currently not available. This study was designed to determine the effects of testosterone on glucose uptake in adipocytes. Glucose uptake was assessed with 2-[(3)H] deoxyglucose in 3T3-L1 adipocytes. GLUT4 translocation was evaluated in plasma membrane (PM) sheets and PM fractions by immunofluorescence and immunoblotting, respectively. Activation of GLUT4 translocation-related protein kinases, including Akt, AMPK, LKB1, CaMKI, CaMKII, and Cbl was followed by immunoblotting. Expression levels of androgen receptor (AR) mRNA and AR translocation to the PM were assessed by real-time RT-PCR and immunoblotting, respectively. The results showed that both high-dose (100 nM) testosterone and testosterone-BSA increased glucose uptake and GLUT4 translocation to the PM, independently of the intracellular AR. Testosterone and testosterone-BSA stimulated the phosphorylation of AMPK, LKB1, and CaMKII. The knockdown of LKB1 by siRNA attenuated testosterone- and testosterone-BSA-stimulated AMPK phosphorylation and glucose uptake. These results indicate that high-dose testosterone and testosterone-BSA increase GLUT4-dependent glucose uptake in 3T3-L1 adipocytes by inducing the LKB1/AMPK signaling pathway.
authors.affiliation: Department of Endocrinology and Metabolism, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, 465 Kajii-cho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Kazuteru
authors.initials: K
authors.lastname: Mitsuhashi
authors.affiliation: Department of Endocrinology and Metabolism, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, 465 Kajii-cho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan. semmarut@koto.kpu-m.ac.jp.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Senmaru
authors.affiliation: Department of Endocrinology and Metabolism, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, 465 Kajii-cho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Fukuda
authors.affiliation: Department of Endocrinology and Metabolism, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, 465 Kajii-cho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yamazaki
authors.affiliation: Department of Ophthalmology, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, Kyoto, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Shinomiya
authors.affiliation: Department of Ophthalmology, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, Kyoto, Japan.
authors.forename: Morio
authors.initials: M
authors.lastname: Ueno
authors.affiliation: Department of Ophthalmology, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, Kyoto, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kinoshita
authors.affiliation: Department of Obstetrics and Gynecology, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, Kyoto, Japan.
authors.forename: Jo
authors.initials: J
authors.lastname: Kitawaki
authors.affiliation: Radioisotope Center, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Katsuyama
authors.affiliation: Institute of Bio-Response Informatics, Kyoto, Japan.
authors.forename: Muneo
authors.initials: M
authors.lastname: Tsujikawa
authors.affiliation: Institute of Bio-Response Informatics, Kyoto, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Obayashi
authors.affiliation: Department of Endocrinology and Metabolism, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, 465 Kajii-cho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Nakamura
authors.affiliation: Department of Endocrinology and Metabolism, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, 465 Kajii-cho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Michiaki
authors.initials: M
authors.lastname: Fukui
mesh_terms: D041721:3T3-L1 Cells; D055372:AMP-Activated Protein Kinases / Q000502:physiology; D017667:Adipocytes / Q000187:drug effects* / Q000378:metabolism*; D000818:Animals; D050260:Carbohydrate Metabolism / Q000187:drug effects; D005947:Glucose / Q000493:pharmacokinetics*; D051275:Glucose Transporter Type 4 / Q000378:metabolism*; D051379:Mice; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism / Q000502:physiology; D021381:Protein Transport / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D013739:Testosterone / Q000494:pharmacology*
chemical_list: D051275:Glucose Transporter Type 4; D013739:Testosterone; D017346:Protein Serine-Threonine Kinases; C491654:Stk11 protein, mouse; D055372:AMP-Activated Protein Kinases; D005947:Glucose
keywords: AMPK signaling; GLUT4 translocation; Glucose uptake; Non-genomic action; Testosterone