Agouti-related protein

Appetite-stimulating. Neuropeptide modulators and gut hormones with orexigenic effects are neuropeptide Y (NPY), agouti-related protein (AGRP), melaninconcentrating hormone (MCH), endocannabinoids, galanin, ghrelin and others. 

Young Y Zeni L Rosenfeld R.D., Stark K.L., Rohde M.F., and Haniu M. (1999), Disulfide assignment of the C-terminal cysteine knot of agouti-related protein (AGRP) by direct sequencing analysis, J. Peptide Res. 54, 514-521. 

Disulfide Connectivities of Human Agouti-Related Protein (66-112) (3) 50 ... 

Dinulescu DM, Cone RD (2000) Agouti and agouti-related protein analogies and contrasts. J Biol Chem 275 6695-6698... 

Ollmann, M. M., Wilson, B. D., Yang, Y.-K., Kerns, J. A, Chen, Y and Gantz, L, and Barsh, G. S. (1997). Antagonism of central melanocortin receptors in vitro and in vivo by agouti-related protein. Science 278,13S-138. 

Other peptides which affect feeding behaviour are found in the hypothalamus. They include the orexigenic peptides neuropeptide Y (NPY) and agouti-related protein (AgRp), and the anorexic peptides melanocyte-stimulating hormone (MSH) and cocaine- and amphetamine-regulated transcript (CART) (see below). 

Hanada R, Nakazato M. Matsukura S, Murakami N, Yoshimatsu H. Sakata T. Differential regulation of melanin-concentrating hormone and orexin genes in the agouti-related protein/melanocortin-4 receptor system. Biochem Biophys Res Commun 2000 268 88-91. 

Mahogany, a single-pass transmembrane protein that modulates the activity of agouti protein and agouti-related protein (AGRP). It is an ancillary protein of the melanocortin system. Mahogany is expressed primarily in the brain, especially in the hypothalamus, and in the skin. It is involved in mammalian coat coloration [T. M. Gunn et al.. Nature 1999, 398, 152]. 

Dubem, B. et al.. Mutational analysis of melanocortin-4-receptor, agouti related protein and alpha-melanocyte-stimulating hormone genes in severely obese children, J. Pediatr., 139, 204-209, 2001. 

Even if an over-simplification, this first order-second order model is useful in understanding how leptin signalling in the brain is translated into whole animal responses. The ARC contains two major neuronal populations (Gao and Horvath, 2007, Schwartz et al, 2000). The first population produces the peptides pro-opiomelanocortin (POMC) and cocaine and amphetamine related transcript (CART). Leptin increases POMC synthesis and processing into anorexic neuropeptides such as the melanocortin a-melanocyte stimulating hormone (oMSH). The second population of neurons is the diametrical opposite to POMC neurons They produce the orexigenic agouti related protein (AGRP) and neuropeptide Y (NPY) and leptin inhibits their production (Schwartz et al, 2000). 

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