The hypothalamic satiety peptide CART is expressed in anorectic and non-anorectic pancreatic islet tumors and in the normal islet of Langerhans

The hypothalamic satiety peptide CART (cocaine and amphetamine regulated tr anscript) is expressed at high levels in anorectic rat glucagonomas but not in hypoglycemic insulinomas, However, a non-anorectic metastasis derived f rom the glucagonoma retained high CART expression levels and produced circu lating CART levels comparable to that of the anorectic tumors. Moreover, di stinct glucagonoma lines derived by stable HES-1 transfection of the insuli noma caused severe anorexia but retained low circulating levels of CART com parable to that of insulinoma bearing or control rats. Islet tumor associat ed anorexia and circulating CART levels are thus not correlated, and in lin e with this peripheral administration of CART (5-50 mg/kg) produced no effe ct on feeding behavior. In the rat two alternatively spliced forms of CART mRNA exist and quantitative PCR revealed expression of both forms in the hy pothalamus, in the different islet tumors, and in the islets of Langerhans, Immunocytochemistry as well as in situ hybridization localized CART expres sion to the somatostatin producing islet D cell, A potential endocrine/para crine role of islet CART remains to be clarified. (C) 1999 Federation of Eu ropean Biochemical Societies.