Sex differences in brown adipose tissue thermogenic features during caloric restriction.
Caloric restriction (CR) studies have shown that females rats conserve energy more efficiently, showing a higher resistance to weight loss and higher protection of vital organs mass than male rats. Gender-dependent inactivation of thermogenesis in brown adipose tissue (BAT) has been proposed as one of these possible energy conserving mechanisms. To study the changes underlying this inactivation in rats, a three month study with 40% CR was undertaken to unravel the effects on BAT recruitment. Under ad libitum conditions female rats had greater BAT recruitment and greater oxygen consumption than their male counterparts. Total and mitochondrial protein, as well as triglyceride and DNA content were more reduced in restricted female rats than in restricted males. Similarly, the levels of key BAT functional proteins (UCP1, LPL, HSL, TFAM) were more reduced in restricted females, whereas no changes were found in mitochondrial DNA levels (mtDNA) and OXPHOS activities in males and females. Furthermore, alpha (2A)/beta (3) adrenergic receptor ratio remained constant in male rats whereas in female rats CR increased 60%. In conclusion, our results suggest that female rats, whose BAT thermogenic activity is higher in ad libitum conditions, is depressed during CR. This inactivation involves the mitochondrial differentiation process and lipolytic system and could be due, at least in part, to the unfavourable adrenergic receptor balance for thermogenic activation.
Valle
Adamo
A
Grup de Metabolisme Energètic i Nutrició. Departament de Biologia Fonamental i Ciències de la Salut. Institut Universitari d'Investigació en Ciències de la Salut (IUNICS). Universitat de les Illes Balears, Palma de Mallorca, Spain.
García-Palmer
Francisco J
FJ
Oliver
Jordi
J
Roca
Pilar
P
D002001:Adipose Tissue, Brown / Q000737:chemistry* / Q000201:enzymology; D000818:Animals; D015992:Body Mass Index; D001835:Body Weight; D031204:Caloric Restriction; D004272:DNA, Mitochondrial / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D005260:Female; D007473:Ion Channels / Q000378:metabolism; D008071:Lipoprotein Lipase / Q000378:metabolism; D008297:Male; D024101:Mitochondrial Proteins / Q000378:metabolism; D010085:Oxidative Phosphorylation; D010101:Oxygen Consumption; D051381:Rats; D011941:Receptors, Adrenergic / Q000378:metabolism; D012737:Sex Factors; D002787:Sterol Esterase / Q000378:metabolism; D022722:Thermogenesis; D014157:Transcription Factors / Q000378:metabolism; D000071256:Uncoupling Protein 1
D004272:DNA, Mitochondrial; D004268:DNA-Binding Proteins; D007473:Ion Channels; D024101:Mitochondrial Proteins; D011941:Receptors, Adrenergic; C499631:TFAM protein, human; D014157:Transcription Factors; C000604371:UCP1 protein, human; C000604373:Ucp1 protein, rat; D000071256:Uncoupling Protein 1; D002787:Sterol Esterase; D008071:Lipoprotein Lipase