Transgenic expression in the hypothalamus of syndecan-1, a cell surface heparan sulfate proteoglycan (HSPG) and modulator of ligand-receptor encounters, produces mice with hyperphagia and maturity-onset obesity resembling mice with reduced action of alpha melanocyte stimulating hormone (alphaMSH). Via their HS chains, syndecans potentiate the action of agouti-related protein and agouti signalin...

A little more than a decade ago, the molecular basis of the lipostat was largely unknown. At that time, many laboratories were at work attempting to clone the genes encoding the obesity, diabetes, fatty, tubby and agouti loci, with the hope that identification of these obesity genes would help shed light on the process of energy homeostasis, appetite and energy expenditure. Characterization of ...

Oxidative and inflammatory stress have been implicated as major contributors to the aging process. Dietary Ca reduced both factors in short-term interventions, while milk exerted a greater effect than supplemental Ca. In this work, we examined the effects of life-long supplemental and dairy calcium on lifespan and life-span related biomarkers in aP2-agouti transgenic (model of diet-induced obes...

Human and Dark Agouti rat liver microsomes were analyzed for caffeine metabolism focusing on demethylase activity by using a simplified isocratic HPLC method. Results showed that, despite interspecies quantitative and qualitative differences on caffeine metabolism, mainly demethylated caffeine metabolites were detected in both species. Humans showed interindividual quantitative differences in c...

AMP-activated protein kinase (AMPK) plays a crucial role in both cellular and whole body energy homeostasis. Here we demonstrate that the muscarinic receptor agonist carbachol activates AMPKalpha1-containing complexes in the human SH-SY5Y cell line via a mechanism specific for the AMPK upstream kinase, Ca(2+)/calmodulin-dependent protein kinase kinase beta. Activation of AMPK inhibits mRNA expr...

In this study, the occurrence of antibodies to Toxoplasma gondii in Brazilian agouti (Dasyprocta aguti) was compared by modified agglutination test (MAT) and indirect fluorescent antibody test (IFAT) using anti-capybara conjugate. Sera from 109 animals were tested using MAT (1:25 cut-off) and IFAT (1:16 cut-off); 19% were positive by MAT, and 18% were positive by IFAT. Overall, the 17 IFAT-posi...

The effects of perirhinal cortex lesions in rats on spatial memory might depend on the choice of strain. The present study, therefore, compared perirhinal lesions in Sprague-Dawley rats (associated with deficits) with Dark Agouti rats (associated with null effects). Tests of reference memory and working memory in the water maze failed to provide evidence that perirhinal lesions disrupt overall ...

The hair follicle is a model system for studying epithelial-mesenchymal interactions during organogenesis. Although analysis of the epithelial contribution to these interactions has progressed rapidly, the lack of tools to manipulate gene expression in the mesenchymal component, the dermal papilla, has hampered progress towards understanding the contribution of these cells. In this work, Corin ...

The melanocortin system is a complex control center that regulates various physiological pathways, which include skin pigmentation, steroidogenesis, sexual function, sebaceous lipid production, energy and weight homeostasis, and food satiety. [1,2] This system consists of five G-protein coupled receptors (MC1R-MC5R), four known endogenous agonists, and two known endogenous antagonists. [2, 3] T...