Melatonin improves insulin sensitivity independently of weight loss in old obese rats

Melatonin improves insulin sensitivity independently of weight loss in old obese rats

Author Zanuto, Ricardo Google Scholar
Siqueira-Filho, Mario A. Google Scholar
Caperuto, Luciana C. Autor UNIFESP Google Scholar
Bacurau, Reury Frank Pereira Google Scholar
Hirata, Emiko Autor UNIFESP Google Scholar
Peliciari-Garcia, Rodrigo A. Google Scholar
Amaral, Fernanda Gaspar do Google Scholar
Marcal, Anderson C. Google Scholar
Ribeiro, Luciene M. Google Scholar
Camporez, Joao P. G. Google Scholar
Carpinelli, Angelo Rafael Google Scholar
Bordin, Silvana Google Scholar
Cipolla-Neto, Jose Google Scholar
Carvalho, Carla R. O. Google Scholar
Institution Universidade de São Paulo (USP)
Universidade Federal de São Paulo (UNIFESP)
Abstract In aged rats, insulin signaling pathway (ISP) is impaired in tissues that play a pivotal role in glucose homeostasis, such as liver, skeletal muscle, and adipose tissue. Moreover, the aging process is also associated with obesity and reduction in melatonin synthesis from the pineal gland and other organs. the aim of the present work was to evaluate, in male old obese Wistar rats, the effect of melatonin supplementation in the ISP, analyzing the total protein amount and the phosphorylated status (immunoprecipitation and immunoblotting) of the insulin cascade components in the rat hypothalamus, liver, skeletal muscle, and periepididymal adipose tissue. Melatonin was administered in the drinking water for 8- and 12 wk during the night period. Food and water intake and fasting blood glucose remained unchanged. the insulin sensitivity presented a 2.1-fold increase both after 8- and 12 wk of melatonin supplementation. Animals supplemented with melatonin for 12 wk also presented a reduction in body mass. the acute insulin-induced phosphorylation of the analyzed ISP proteins increased 1.3- and 2.3-fold after 8- and 12 wk of melatonin supplementation. the total protein content of the insulin receptor (IR) and the IR substrates (IRS-1, 2) remained unchanged in all investigated tissues, except for the 2-fold increase in the total amount of IRS-1 in the periepididymal adipose tissue. Therefore, the known age-related melatonin synthesis reduction may also be involved in the development of insulin resistance and the adequate supplementation could be an important alternative for the prevention of insulin signaling impairment in aged organisms.
Keywords aging
insulin
insulin signaling pathway
melatonin
obesity
Language English
Sponsor Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Date 2013-09-01
Published in Journal of Pineal Research. Hoboken: Wiley-Blackwell, v. 55, n. 2, p. 156-165, 2013.
ISSN 0742-3098 (Sherpa/Romeo, impact factor)
Publisher Wiley-Blackwell
Extent 156-165
Origin http://dx.doi.org/10.1111/jpi.12056
Access rights Closed access
Type Article
Web of Science ID WOS:000322744600006
URI http://repositorio.unifesp.br/handle/11600/36734

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