Ghrelin, peptide YY and their receptors: gene expression in brain from subjects with and without Prader-Willi syndrome.

Ghrelin and peptide YY (PYY) are peptides generally produced by the gastrointestinal organs which are involved in appetite regulation via highly specialized centers in the brain. Abnormal plasma ghrelin and PYY levels compared with controls have been reported for subjects with Prader-Willi syndrome (PWS) which is characterized by infantile hypotonia, poor suck reflex and failure to thrive followed by hyperphagia and marked obesity in early childhood. We studied gene expression of ghrelin, peptide YY, and their receptors (i.e., GHS-R1a, GHS-R1b, and NPY2R) in six different brain regions (frontal cortex, temporal cortex, visual cortex, pons, medulla, and hypothalamus) obtained from three subjects with PWS, two individuals with Angelman syndrome, and six controls to determine if expression of these genes is detectable in different regions of the brain in subjects with and without PWS. In general, expression of these genes using RT-PCR was detected in all subjects and no obvious differences were seen in their pattern of expression between subjects with or without PWS. Additional studies including quantitative gene expression measurements will be required to further evaluate the role of these genes in the eating disorder seen in PWS.