title: Voluntary exercise contributed to an amelioration of abnormal feeding behavior, locomotor activity and ghrelin production concomitantly with a weight reduction in high fat diet-induced obese rats.
abstract: In the present study, effects of voluntary exercise in an obese animal model were investigated in relation to the rhythm of daily activity and ghrelin production. Male Sprague-Dawley rats were fed either a high fat diet (HFD) or a chow diet (CD) from four to 16 weeks old. They were further subdivided into either an exercise group (HFD-Ex, CD-Ex) with a running wheel for three days of every other week or sedentary group (HFD-Se, CD-Se). At 16 weeks old, marked increases in body weight and visceral fat were observed in the HFD-Se group, together with disrupted rhythms of feeding and locomotor activity. The induction of voluntary exercise brought about an effective reduction of weight and fat, and ameliorated abnormal rhythms of activity and feeding in the HFD-Ex rats. Wheel counts as voluntary exercise was greater in HFD-Ex rats than those in CD-Ex rats. The HFD-obese had exhibited a deterioration of ghrelin production, which was restored by the induction of voluntary exercise. These findings demonstrated that abnormal rhythms of feeding and locomotor activity in HFD-obese rats were restored by infrequent voluntary exercise with a concomitant amelioration of the ghrelin production and weight reduction. Because ghrelin is related to food anticipatory activity, it is plausible that ghrelin participates in the circadian rhythm of daily activity including eating behavior. A beneficial effect of voluntary exercise has now been confirmed in terms of the amelioration of the daily rhythms in eating behavior and physical activity in an animal model of obesity.
authors.affiliation: Institute of Animal Experimentation, Kurume University School of Medicine, Kurume 830-0011, Japan.
authors.forename: Hiroharu
authors.initials: H
authors.lastname: Mifune
authors.affiliation: Division of Endocrinology and Metabolism, Kurume University School of Medicine, Kurume 830-0011, Japan. Electronic address: tajiriy@med.kurume-u.ac.jp.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Tajiri
authors.affiliation: Department of Physiology, Kurume University School of Medicine, Kurume 830-0011, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Nishi
authors.affiliation: Division of Endocrinology and Metabolism, Kurume University School of Medicine, Kurume 830-0011, Japan.
authors.forename: Kento
authors.initials: K
authors.lastname: Hara
authors.affiliation: Division of Endocrinology and Metabolism, Kurume University School of Medicine, Kurume 830-0011, Japan.
authors.forename: Shimpei
authors.initials: S
authors.lastname: Iwata
authors.affiliation: Division of Endocrinology and Metabolism, Kurume University School of Medicine, Kurume 830-0011, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Tokubuchi
authors.affiliation: Department of Exercise Physiology, Institute of Health and Sports Science, Kurume University, Kurume 839-8502, Japan.
authors.forename: Ryouichi
authors.initials: R
authors.lastname: Mitsuzono
authors.affiliation: Division of Endocrinology and Metabolism, Kurume University School of Medicine, Kurume 830-0011, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yamada
authors.affiliation: Molecular Genetics, Life Science Institute, Kurume University, Kurume 839-0864, Japan.
authors.forename: Masayasu
authors.initials: M
authors.lastname: Kojima
mesh_terms: D000818:Animals; D004041:Dietary Fats / Q000009:adverse effects* / Q000494:pharmacology; D005247:Feeding Behavior / Q000187:drug effects*; D054439:Ghrelin / Q000378:metabolism*; D008124:Locomotion / Q000187:drug effects*; D008297:Male; D009765:Obesity / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D010805:Physical Conditioning, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D015431:Weight Loss / Q000187:drug effects*
chemical_list: D004041:Dietary Fats; D054439:Ghrelin
keywords: Daily rhythm; Feeding behavior; Ghrelin; Locomotor activity; Voluntary exercise