Metabolic adaptations in the adipose tissue that underlie the body fat mass gain in middle-aged rats

Autor(es)

Laurato Sertie, Rogerio Antonio ^[1] ; Caminhotto, Rennan de Oliveira ^[1] ; Andreotti, Sandra ^[1] ; Campana, Amanda Baron ^[1] ; Gomes de Proenca, Andre Ricardo ^[2] ; de Castro, Natalie Carolina ^[1] ; Lima, Fabio Bessa ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Biomed Sci, Dept Physiol & Biophys, BR-05508 Sao Paulo - Brazil

^[2] Univ Estadual Campinas, Fac Sci Appl, Biotechnol Lab, Limeira, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: AGE; v. 37, n. 5 OCT 2015.
• Citações Web of Science: 1

Resumo

Little is known about adipocyte metabolism during aging process and whether this can influence body fat redistribution and systemic metabolism. To better understand this phenomenon, two animal groups were studied: young-14 weeks old-and middle-aged-16 months old. Periepididymal (PE) and subcutaneous (SC) adipocytes were isolated and tested for their capacities to perform lipolysis and to incorporate D-{[}U-C-14]-glucose, D-{[}U-C-14]-lactate, and {[}9,10(n)-H-3]-oleic acid into lipids. Additionally, the morphometric characteristics of the adipose tissues, glucose tolerance tests, and biochemical determinations (fasting glucose, triglycerides, insulin) in blood were performed. The middle-aged rats showed adipocyte (PE and SC) hypertrophy and glucose intolerance, although there were no significant changes in fasting glycemia and insulin. Furthermore, PE tissue revealed elevated rates (+50 %) of lipolysis during beta-adrenergic-stimulation. There was also an increase (+62 %) in the baseline rate of glucose incorporation into lipids in the PE adipocytes, while these PE cells were almost unresponsive to insulin stimulation and less responsive (a 34 % decrease) in the SC tissue. Also, the capacity of oleic acid esterification was elevated in baseline state and with insulin stimulus in the PE tissue (+90 and 82 %, respectively). Likewise, spontaneous incorporation of lactate into lipids in the PE and SC tissues was higher (+100 and 11 %, respectively) in middle-aged rats. We concluded that adipocyte metabolism of middle-aged animals seems to strongly favor cellular hypertrophy and increased adipose mass, particularly the intra-abdominal PE fat pad. In discussion, we have interpreted all these results as a metabolic adaptations to avoid the spreading of fat that can reach tissues beyond adipose protecting them against ectopic fat accumulation. However, these adaptations may have the potential to lead to future metabolic dysfunctions seen in the senescence. (AU)

• Processo FAPESP: 14/15210-3 - Investigação dos aspectos moleculares da lipogênese/lipólise e da adipogênese/apoptose em ratos de meia idade suplementados ou não com melatonina
• Beneficiário: Fabio Bessa Lima
• Modalidade de apoio: Auxílio à Pesquisa - Regular