Central action of CART induces neuronal activation in the paraventricular and dorsomedial hypothalamus of diet-induced obese and lean mice.

The cocaine- and amphetamine-regulated transcript (CART) is a peptide commonly studied in the feeding behavior, but it exerts an important role in the autonomic and cardiovascular control as well. It is known that exogenous administration of CART in the central nervous system can elicit increase in blood pressure of both conscious and anesthetized rodents, but little is known whether these central effects might differ between lean and obese animals. We have recently shown that diet-induced obese mice that developed hypertension presented an upregulation of CART levels in the dorsomedial nucleus of hypothalamus, while obese normotensive ones had not.

Uncaria tomentosa improves insulin sensitivity and inflammation in experimental NAFLD.

We investigated the effect of the crude herbal extract from Uncaria tomentosa (UT) on non-alcoholic fatty liver disease (NAFLD) in two models of obesity: high fat diet (HFD) and genetically obese (ob/ob) mice. Both obese mouse models were insulin resistant and exhibited an abundance of lipid droplets in the hepatocytes and inflammatory cell infiltration in the liver, while only the HFD group had collagen deposition in the perivascular space of the liver. UT treatment significantly reduced liver steatosis and inflammation in both obese mouse models.

Dehydroepiandrosterone supplementation is not beneficial in the late postmenopausal period in diet-induced obese rats.

Aims: Dehydroepiandrosterone (DHEA) is an adrenal steroid hormone that is a precursor of sexual hormones. It is reduced during aging and is strongly associated with insulin resistance and obesity. There is evidence for beneficial effects of this steroid, in both human and animal models, during perimenopause.

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

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.

Postpartum glycemic homeostasis in early lactating rats is accompanied by transient and specific increase of soleus insulin response through IRS2/AKT pathway.

It is known that at the moment of delivery immediate lost of conceptus (main site of glucose disposal in late pregnancy) is not able to disturb glucose homeostasis in early lactating mothers. However, the mechanism by which this adaptation takes place in early lactation is still unknown. Most studies concerning insulin sensitivity in lactating rats were carried out at 11-13 days postpartum and did not describe functional changes in insulin response in early lactation.

Distinct regulation of IRS proteins in adipose tissue from obese aged and dexamethasone-treated rats.

In the present study, we investigated the protein levels and phosphorylation status of the insulin receptor and insulin receptor substrates (IRS-1, IRS-2, and IRS-3) as well as their association with PI(3)-kinase in the rat adipose tissue of two models of insulin resistance: dexamethasone treatment and aging. AKT and atypical PKC phosphorylation detection were also performed. Both models showed decreased insulin-induced IRS-1 and IRS-2 tyrosine phosphorylation, accompanied by reduced protein levels of IRS-1 and IRS-2.