title: Weight loss by calorie restriction versus bariatric surgery differentially regulates the hypothalamo-pituitary-adrenocortical axis in male rats.
abstract: Behavioral modifications for the treatment of obesity, including caloric restriction, have notoriously low long-term success rates relative to bariatric weight-loss surgery. The reasons for the difference in sustained weight loss are not clear. One possibility is that caloric restriction alone activates the stress-responsive hypothalamo-pituitary-adrenocortical (HPA) axis, undermining the long-term maintenance of weight loss, and that this is abrogated after bariatric surgery. Accordingly, we compared the HPA response to weight loss in five groups of male rats: (1) high-fat diet-induced obese (DIO) rats treated with Roux-en-Y gastric bypass surgery (RYGB, n = 7), (2) DIO rats treated with vertical sleeve gastrectomy (VSG, n = 11), (3) DIO rats given sham surgery and subsequently restricted to the food intake of the VSG/RYGB groups (Pair-fed, n = 11), (4) ad libitum-fed DIO rats given sham surgery (Obese, n = 11) and (5) ad libitum chow-fed rats given sham surgery (Lean, n = 12). Compared with Lean controls, food-restricted rats exhibited elevated morning (nadir) non-stress plasma corticosterone concentration and increased hypothalamic corticotropin-releasing hormone and vasopressin mRNA expression, indicative of basal HPA activation. This was largely prevented when weight loss was achieved by bariatric surgery. DIO increased HPA activation by acute (novel environment) stress and this was diminished by bariatric surgery-, but not pair-feeding-, induced weight loss. These results indicate that the HPA axis is differentially affected by weight loss from caloric restriction versus bariatric surgery, and this may contribute to the differing long-term effectiveness of these two weight-loss approaches.
authors.affiliation: Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism .
authors.forename: Bernadette E
authors.initials: BE
authors.lastname: Grayson
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Hakala-Finch
authors.forename: Melani
authors.initials: M
authors.lastname: Kekulawala
authors.forename: Holly
authors.initials: H
authors.lastname: Laub
authors.forename: Ann E
authors.initials: AE
authors.lastname: Egan
authors.forename: Ilana B
authors.initials: IB
authors.lastname: Ressler
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Woods
authors.forename: James P
authors.initials: JP
authors.lastname: Herman
authors.forename: Randy J
authors.initials: RJ
authors.lastname: Seeley
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Benoit
authors.forename: Yvonne M
authors.initials: YM
authors.lastname: Ulrich-Lai
mesh_terms: D000818:Animals; D031204:Caloric Restriction; D003345:Corticosterone / Q000097:blood; D003346:Corticotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism; D059305:Diet, High-Fat; D004195:Disease Models, Animal; D005743:Gastrectomy; D015390:Gastric Bypass; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D009765:Obesity / Q000097:blood / Q000178:diet therapy* / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D010913:Pituitary-Adrenal System / Q000378:metabolism / Q000503:physiopathology*; D012333:RNA, Messenger / Q000378:metabolism; D020318:Rats, Long-Evans; D013312:Stress, Physiological; D013997:Time Factors; D014667:Vasopressins / Q000235:genetics / Q000378:metabolism; D015431:Weight Loss
chemical_list: D012333:RNA, Messenger; D014667:Vasopressins; D003346:Corticotropin-Releasing Hormone; D003345:Corticosterone
keywords: Adrenocorticotropic hormone; Roux-en-Y gastric bypass; corticosterone; corticotropin-releasing hormone; pair-feeding; vertical sleeve gastrectomy