Obesity Increases Mitogen-Activated Protein Kinase Phosphatase-3 Levels in the Hypothalamus of Mice.

Mitogen-activated Protein Kinase Phosphatase 3 (MKP-3) has been involved in the negative regulation of insulin signaling. The absence of MKP-3 is also associated with reduced adiposity, increased energy expenditure and improved insulin sensitivity. The MKP-3 is known as the main Erk1/2 phosphatase and FoxO1 activator, which has repercussions on the gluconeogenesis pathway and hyperglycemia in obese mice.

Overexpression of Mitogen-activated protein kinase phosphatase-3 (MKP-3) reduces FoxO1 phosphorylation in mice hypothalamus.

The mitogen-activated kinase phosphatase-3 (MKP-3) has gained great importance in the scientific community by acting as a regulator of the cell cycle through dephosphorylation of FoxO1, an important transcription factor involved in the insulin intracellular signaling cascade. When dephosphorylated and translocated to the nuclei, FoxO1 can promote the transcription of orexigenic neuropeptides (NPY/AgRP) in the hypothalamus, whereas insulin signaling is responsible for the disruption of this process. However, it is not understood if the hypothalamic activation of MKP-3 affects FoxO1 phosphorylation, and we hypothesized that MKP-3 overexpression reduces the capacity of the insulin signal to phosphorylate FoxO1.

Acute Exercise Decreases Tribbles Homolog 3 Protein Levels in the Hypothalamus of Obese Rats.

Purpose: This study aims to evaluate the effects of acute exercise on tribbles homolog 3 (TRB3) protein levels and on the interaction between TRB3 and Akt proteins in the hypothalamus of obese rats. In addition, we evaluated the relationship between TRB3 and endoplasmic reticulum (ER) stress and verified whether an acute exercise session influences them.

Methods: In the first part of the study, the rats were divided into three groups: control (lean), fed standard rodent chow; DIO, fed a high-fat diet; and DIO-EXE, fed a high-fat diet and submitted to a swimming acute exercise protocol.

Effects of different intensities of physical exercise on insulin sensitivity and protein kinase B/Akt activity in skeletal muscle of obese mice.

Objective: To investigate the effects of different intensities of acute exercise on insulin sensitivity and protein kinase B/Akt activity in skeletal muscle of obese mice.

Methods: Swiss mice were randomly divided into four groups, and fed either a standard diet (control group) or high fat diet (obese sedentary group and obese exercise group 1 and 2) for 12 weeks. Two different exercise protocols were used: swimming for 1 hour with or without an overload of 5% body weight.