title: Adiponectin receptor 2 is regulated by nutritional status, leptin and pregnancy in a tissue-specific manner.
abstract: The aim of the present work was to study the regulation of circulating adiponectin levels and the expression of adiponectin receptor 2 (Adipo-R2) in several rat tissues in relation to fasting, leptin challenge, pregnancy, and chronic undernutrition. Using real-time PCR, we found Adipo-R2 mRNA expression in the liver, stomach, white and brown adipose tissues (WAT and BAT) of adult rats. Immunohistochemical studies confirmed protein expression in the same tissues. Adipo-R2 mRNA levels were decreased in liver after fasting, with no changes in the other tissues. Leptin decreased Adipo-R2 expression in liver and stomach, but increased its expression in WAT and BAT. Chronic caloric restriction in normal rats increased Adipo-R2 gene expression in stomach, while it decreased hepatic Adipo-R2 levels in pregnant rats. Using radioimmunoassay, we found that plasma adiponectin levels were diminished by fasting and leptin. Conversely, circulating adiponectin was increased in food-restricted rats, whereas its levels decreased in food-restricted pregnant rats by the end of gestation. In conclusion our findings provide the first evidence that (a) Adipo-R2 mRNA is regulated in a tissue-specific manner by fasting, but leptin is not responsible for those changes; (b) chronic caloric restriction in normal and pregnant rats also regulate Adipo-R2 mRNA in a tissue-specific manner; and (c) Adipo-R2 mRNA does not show a clear correlation with plasma adiponectin levels.
authors.affiliation: Department of Physiology, School of Medicine, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782 Santiago de Compostela, Spain.
authors.forename: Carmen Ruth
authors.initials: CR
authors.lastname: González
authors.forename: Jorge Eduardo
authors.initials: JE
authors.lastname: Caminos
authors.forename: Rosalía
authors.initials: R
authors.lastname: Gallego
authors.forename: Sulay
authors.initials: S
authors.lastname: Tovar
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Vázquez
authors.forename: María Fernanda
authors.initials: MF
authors.lastname: Garcés
authors.forename: Miguel
authors.initials: M
authors.lastname: Lopez
authors.forename: Tomás
authors.initials: T
authors.lastname: García-Caballero
authors.forename: Manuel
authors.initials: M
authors.lastname: Tena-Sempere
authors.forename: Rubén
authors.initials: R
authors.lastname: Nogueiras
authors.forename: Carlos
authors.initials: C
authors.lastname: Diéguez
mesh_terms: D052242:Adiponectin / Q000097:blood; D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D031204:Caloric Restriction / Q000379:methods; D005215:Fasting / Q000378:metabolism; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000502:physiology; D020738:Leptin / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009752:Nutritional Status / Q000502:physiology*; D011247:Pregnancy / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011863:Radioimmunoassay / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D054419:Receptors, Adiponectin / Q000235:genetics / Q000378:metabolism*; D018709:Statistics, Nonparametric; D013270:Stomach / Q000187:drug effects
chemical_list: D052242:Adiponectin; D020738:Leptin; D012333:RNA, Messenger; D054419:Receptors, Adiponectin; C506573:adiponectin receptor 2, rat