Quantification of hypothalamic mRNA changes during fasting using phosphor imaging

Growing evidence indicates that specific hypothalamic neuropeptides, such a s neuropeptide Y (NPY), act as critical control systems for the regulation of food intake and body weight, NPY is the most prevalent peptide in the ce ntral nervous system (CNS) of a variety of mammals and NPY cell bodies in t he arcuate nucleus of the hypothalamus seem to be critical effecters in the control of feeding. Exogenous NPY administered into the CNS produces robus t increases in food intake and repeated administration results in increased body Weight(1-3). In contrast, corticotropin-releasing hormone (CRH) decre ases food intake and repeated administration produces decreased body weight (4). If these hypothalamic systems are important in endogenous control of f ood intake during periods of negative energy balance, NPY activity should i ncrease while CRH activity should decrease(5,6). To test this hypothesis we measured NPY and CRH gene expression using radiolabelled oligonucleotide p robes. We also present a new method for quantifying in situ hybridization d ata by using a phosphor imaging system to locate and quantify those probes.