title: Exercise training ameliorates glucosamine-induced insulin resistance in ovariectomized rats.
abstract: Glucosamine (GlcN), which has been reported to induce insulin resistance (IR), is a popular nutritional supplement used to treat osteoarthritis in menopausal women. We previously demonstrated that GlcN treatment caused IR in ovariectomized rats by reducing the expression of glucose transport protein subtype 4 (GLUT-4) in skeletal muscle. In the present study, we hypothesized that endurance exercise training can reverse GlcN-induced IR.
  
  
  
  Fifty female rats were randomly divided into five groups with 10 rats in each group: (1) sham-operated group; (2) sham-operated group with GlcN treatment for 14 days; (3) ovariectomy (OVX) group; (4) OVX with GlcN treatment; and (5) OVX with GlcN treatment followed by exercise training (running program) for 8 weeks.
  
  
  
  Fasting plasma glucose increased in the OVX + GlcN group, and fasting plasma insulin and the homeostasis model assessment-insulin resistance (HOMA-IR) were significantly higher only in this group. After the rats received exercise training for 8 weeks, no increase in the fasting plasma glucose, insulin, or HOMA-IR was observed. In an intraperitoneal glucose tolerance test, the plasma glucose, plasma insulin, HOMA-IR, and glucose-insulin index were significantly elevated only in the OVX with GlcN treatment group. However, the plasma glucose, plasma insulin, HOMA-IR, and glucose-insulin index decreased after exercise training for 8 weeks, implying that GlcN-induced IR in OVX rats could be reversed through exercise. A histological analysis revealed that exercise training can reduce islet hypertrophy and maintain GLUT-4 in skeletal muscle.
  
  
  
  Exercise training can alleviate IR in OVX rats treated with GlcN. Islet hyperplasia was subsequently prevented. Preserving GLUT-4 expression may be one of the mechanisms by which exercise prevents IR.
authors.affiliation: 1Department of Orthopedics, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung City, Taiwan 2Department of Orthopedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan 3Orthopaedic Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan 4Departments of Orthopedics, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan 5Institute of Physical Education, Health and Leisure Studies, National Cheng Kung University, Tainan, Taiwan 6Department of Physiology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan 7Department of Anatomy, School of Medicine, China Medical University, Taichung, Taiwan 8Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan 9Department of Obstetrics and Gynecology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Chung-Hwan
authors.initials: CH
authors.lastname: Chen
authors.forename: Tsang-Hai
authors.initials: TH
authors.lastname: Huang
authors.forename: Tsung-Lin
authors.initials: TL
authors.lastname: Cheng
authors.forename: Chi-Fen
authors.initials: CF
authors.lastname: Chang
authors.forename: Chau-Zen
authors.initials: CZ
authors.lastname: Wang
authors.forename: Meng-Hsing
authors.initials: MH
authors.lastname: Wu
authors.forename: Lin
authors.initials: L
authors.lastname: Kang
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D005215:Fasting; D005260:Female; D005944:Glucosamine / Q000494:pharmacology*; D005951:Glucose Tolerance Test; D051275:Glucose Transporter Type 4 / Q000032:analysis; D006984:Hypertrophy; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology*; D007515:Islets of Langerhans / Q000187:drug effects / Q000473:pathology; D018482:Muscle, Skeletal / Q000737:chemistry / Q000187:drug effects; D010052:Ovariectomy; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D001786:Blood Glucose; D051275:Glucose Transporter Type 4; D007328:Insulin; D005944:Glucosamine