Co-ativador-1 alfa do receptor ativado por proliferador do peroxissoma (PGC-1 alfa ) : um co-ativador de transcrição genica envolvido com o controle da secreção e ação periferica da insulina

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

Type 2 diabetes mellitus is a multifactorial disease that results from the confluence of at least two distinct events, insulin resistance and failure of the pancreatic beta cell. Recent evidences suggest that common mechanisms may participate in the events that precipitate the development of both insulin resistance and beta cell disarrangement. The characterization of such events may offer new perspectives for a unified therapeutic approach for diabetes. The protein PGC-la fulfills some of the requirements to be included in a list of potential candidates for playing a role in the genesis of both the main mechanisms involved in the development of diabetes. To evaluate the role of this protein in the production and action of insulin we employed an antisense oligonucleotide to PGC-la, which is capable of significantly reducing the expression of this protein. Through this approach it was observed that PGC-la responds to sympathetic stimuli mat inhibit insulin secretion. Such stimuli induce the expression of PGC-la and subsequently of the uncoupling protein-2 (UCP-2). Once induced UCP-2 favors a reduction of ATP production from glucose metabolism and therefore reduces insulin secretion. In addition, the expression of PGC-la was increased in liver and adipose tissue of an animal model of diet-induced obesity and diabetes. The inhibition of PGC-la promoted an increase of insulin secretion, an increase of peripheral insulin action, an improvement of insulin signal transduction and, surprisingly the reversal of diet-induced hepatic steatosis. Thus, PGC-la appears as an attractive potential target for therapeutics in diabetes and related diseases

ASSUNTO(S)

mitocondrias - metabolismo insulina - secreção diabetes resistencia a insulina

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