title: Dioscorea esculenta-induced increase in muscle sex steroid hormones is associated with enhanced insulin sensitivity in a type 2 diabetes rat model.
abstract: The effects of chronic Dioscorea esculenta administration and exercise training on muscle sex steroid hormone levels and insulin resistance in type 2 diabetes rats was assessed. Twenty-week-old male Otsuka Long Evans Tokushima Fatty (OLETF) rats were assigned randomly to the control, D. esculenta treatment, D. esculenta with 5α-reductase inhibitor treatment, or the exercise training groups (running at 25 m/min for 1 h, 5 d/wk; n = 10 each group). Eight weeks of D. esculenta treatment or exercise training significantly attenuated the increase in plasma insulin and fasting glucose levels. Plasma and muscle concentrations of dehydroepiandrosterone and 5α-dihydrotestosterone (DHT) and the expression of 5α-reductase increased significantly in the D. esculenta-treated and exercise training groups, and both treatments led to the upregulation of glucose transporter-4 translocation with concomitant increases in PKB and PKC-ζ/λ phosphorylation. Furthermore, the glucose metabolic clearance rate, which represents insulin sensitivity, increased significantly in both the D. esculenta-treated and exercise training groups. These effects were suppressed by administration of the DHT synthetic inhibitor. Together, these findings suggest that the D. esculenta-induced increase in muscle sex steroid hormone levels helps decrease insulin resistance in type 2 diabetes.-Sato, K., Fujita, S., Iemitsu, M. Dioscorea esculenta-induced increase in muscle sex steroid hormones is associated with enhanced insulin sensitivity in a type 2 diabetes rat model.
authors.affiliation: Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Japan; and sato712@people.kobe-u.ac.jp.|Graduate School of Human Development and Environment, Kobe University, Kobe, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Sato
authors.affiliation: Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Japan; and.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Fujita
authors.affiliation: Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Japan; and.
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Iemitsu
mesh_terms: D000818:Animals; D003687:Dehydroepiandrosterone / Q000235:genetics / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D027742:Dioscorea / Q000737:chemistry*; D005786:Gene Expression Regulation / Q000187:drug effects; D019298:Glucose-6-Phosphate / Q000378:metabolism; D007333:Insulin Resistance; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects*; D010805:Physical Conditioning, Animal; D011897:Random Allocation; D051381:Rats; D020334:Rats, Inbred OLETF; D059467:Transcriptome
chemical_list: D003687:Dehydroepiandrosterone; D019298:Glucose-6-Phosphate
keywords: DHT; diosgenin; exercise; insulin resistance