title: The effects of the melanocortin agonist (MT-II) on subcutaneous and visceral adipose tissue in rodents.
abstract: The melanocortin system is a critical pathway in the regulation of energy balance. In this study, we analyzed the peripheral effects of the synthetic melanocortin agonist melanotan-II (MT-II) in rodents fed a low-fat or high-fat diet. MT-II-treated high-fat diet-induced obese (DIO) mice lost weight and body fat, whereas MT-II-treated low-fat-fed mice maintained their original body weight. Specifically, MT-II treatment led to a general reduction in both visceral and subcutaneous adipose tissue in high-fat-fed mice compared with Vehicle (ad libitum) controls. Vehicle-treated pair-fed DIO mice lost an equivalent amount of body weight compared with MT-II-treated mice but retained more adipose tissue. Pair-fed mice showed a reduction in visceral adipose tissue and no effect on subcutaneous adipose tissue compared with MT-II-treated mice. It is surprising that subcutaneous lean mass was significantly reduced in the pairfed mice. The data were replicated in DIO rats and indicated that MT-II treatment led to a generalized reduction in adipose tissue. These results indicate that peripheral MT-II treatment leads to weight loss that affects both the visceral and subcutaneous fat compartments. This finding illustrates the complexity of analyzing weight-reducing compounds. Although the present data suggest that the anorectic effect of MT-II is primarily a consequence of reduced food intake, the body composition data suggest that other mechanisms are involved.
authors.affiliation: University of Cincinnati School of Medicine, Cincinnati, Ohio, USA. astrader@siumed.edu
authors.forename: April D
authors.initials: AD
authors.lastname: Strader
authors.forename: Haifei
authors.initials: H
authors.lastname: Shi
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Ogawa
authors.forename: Randy J
authors.initials: RJ
authors.lastname: Seeley
authors.forename: Ofer
authors.initials: O
authors.lastname: Reizes
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D050152:Intra-Abdominal Fat / Q000187:drug effects*; D053486:Melanocortins / Q000819:agonists*; D051379:Mice; D008820:Mice, Obese; D009765:Obesity / Q000188:drug therapy; D010456:Peptides, Cyclic / Q000494:pharmacology*; D050151:Subcutaneous Fat / Q000187:drug effects*; D000521:alpha-MSH / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D053486:Melanocortins; D010456:Peptides, Cyclic; C079282:melanotan-II; D000521:alpha-MSH