title: Acute exercise decreases PTP-1B protein level and improves insulin signaling in the liver of old rats.
abstract: It is now commonly accepted that chronic inflammation associated with obesity during aging induces insulin resistance in the liver. In the present study, we investigated whether the improvement in insulin sensitivity and insulin signaling, mediated by acute exercise, could be associated with modulation of protein-tyrosine phosphatase 1B (PTP-1B) in the liver of old rats. Aging rats were subjected to swimming for two 1.5-h long bouts, separated by a 45 min rest period. Sixteen hours after the exercise, the rats were sacrificed and proteins from the insulin signaling pathway were analyzed by immunoblotting. Our results show that the fat mass was increased in old rats. The reduction in glucose disappearance rate (Kitt) observed in aged rats was restored 16 h after exercise. Aging increased the content of PTP-1B and attenuated insulin signaling in the liver of rats, a phenomenon that was reversed by exercise. Aging rats also increased the IRβ/PTP-1B and IRS-1/PTP-1B association in the liver when compared with young rats. Conversely, in the liver of exercised old rats, IRβ/PTP-1B and IRS-1/PTP-1B association was markedly decreased. Moreover, in the hepatic tissue of old rats, the insulin signalling was decreased and PEPCK and G6Pase levels were increased when compared with young rats. Interestingly, 16 h after acute exercise, the PEPCK and G6Pase protein level were decreased in the old exercised group. These results provide new insights into the mechanisms by which exercise restores insulin signalling in liver during aging.
authors: Universidade Estadual Paulista, UNESP, Curso de Pós-Graduação em Ciências da Motricidade Humana, Rio Claro, SP, Brazil.
authors: Leandro Pereira
authors: LP
authors: de Moura
authors: Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Curso de Pós-Graduação em Nutrição, Esporte e Metabolismo. UNICAMP, Limeira, SP, Brazil.
authors: Luciana Santos
authors: LS
authors: Souza Pauli
authors: Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Curso de Pós-Graduação em Nutrição, Esporte e Metabolismo. UNICAMP, Limeira, SP, Brazil.
authors: Dennys Esper
authors: DE
authors: Cintra
authors: Universidade de São Paulo, Escola de Educação Física e Esporte, USP, Ribeirão Preto, SP, Brazil.
authors: Claudio Teodoro
authors: CT
authors: de Souza
authors: Universidade do Extremo Sul Catarinense, Laboratório de Bioquímica e Fisiologia, Santa Catarina, Criciúma, SC, Brazil.
authors: Adelino Sanchez Ramos
authors: ASR
authors: da Silva
authors: Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Curso de Pós-Graduação em Nutrição, Esporte e Metabolismo. UNICAMP, Limeira, SP, Brazil.
authors: Rodolfo
authors: R
authors: Marinho
authors: Universidade Estadual Paulista, UNESP, Curso de Pós-Graduação em Ciências da Motricidade Humana, Rio Claro, SP, Brazil.
authors: Maria Alice Rostom
authors: MAR
authors: de Melo
authors: Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Curso de Pós-Graduação em Nutrição, Esporte e Metabolismo. UNICAMP, Limeira, SP, Brazil.
authors: Eduardo Rochete
authors: ER
authors: Ropelle
authors: Universidade Estadual Paulista, UNESP, Curso de Pós-Graduação em Ciências da Motricidade Humana, Rio Claro, SP, Brazil.|Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Curso de Pós-Graduação em Nutrição, Esporte e Metabolismo. UNICAMP, Limeira, SP, Brazil.|Curso de Ciências do Esporte, FCA-UNICAMP, Rua Pedro Zaccaria, 1300, Jardim Santa Luzia, Limeira, SP, Brazil.
authors: José Rodrigo
authors: JR
authors: Pauli