Prolactin-releasing peptide (PrRP) is a member of the family of RF-amide peptides. These peptides have typical C-terminal sequence -Arg-Phe-NH2 and similar biological effects. PrRP was discovered as an endogenous ligand of an orphan receptor GPR10 while searching for a factor responsible for a prolactin secretion. This effect was not later confirmed and nowadays, PrRP is mainly considered as an anorexigenic peptide. This is supported by a fact that PrRP and GPR10 deficient mice suffer from hyperphagia and late-onset obesity. Besides GPR10, PrRP is bound to NPFF2 receptor whose endogenous ligand is neuropeptide FF (NPFF). In this study, the PrRP's analogues modified at the N-terminus with fatty acids of different lenghts were tested in vitro on binding and activation MAPK/ERK1/2 signalling pathway. In in vivo experiments on food intake, the central anorexigenic effects of lipidized PrRP-analogues were tested provided their crossing blood brain barrier. Binding studies showed that all analogues bound to rat pituitary RC-4B/C cells with high affinity, analogues containing fatty acid with Ki of one order of magnitude lower than native PrRP. High affinity was also confirmed for binding to cells overexpressing GPR10 receptor and cell membranes with overexpressed NPFF2 receptor. All tested analogues...

This work focuses on anorexigenic neuropeptides, cocaine- and amphetamine-regulated transcript (CART) and prolactin-releasing peptide (PrRP), which decrease food intake and body weight. CART peptide is an anorexigenic neuropeptide and, despite many efforts, its receptor has not yet been identified. We found CART peptide specific binding sites in pheochromocytoma PC12 cells. Cells differentiated to neurons increased significantly the number of binding sites. On the other hand, after differentiation to chromaffin cells the number of binding sites was so low that it was impossible to determine their density. To clarify the importance of each of the three disulfide bridges in the CART molecule, analogs with one or two disulfide bridges were synthetized. The biological activity was maintained in analog with two disulfide bridges in positions 74-94 and 88-101. Moreover, we demonstrated the stimulation of JNK and subsequently c-Jun activation in PC12 cells. Neuropeptide PrRP belongs to the RF-amide peptide family and has anorexigenic properties. PrPR has a high affinity to GPR10 and neuropeptide FF (NPFF2) receptor. In our laboratory lipidized analogs of PrRP were synthesized, which are able to decrease food intake after peripheral administration and may cross the blood-brain barrier. We tested biological...

This work focuses on anorexigenic neuropeptides, cocaine- and amphetamine-regulated transcript (CART) and prolactin-releasing peptide (PrRP), which decrease food intake and body weight. CART peptide is an anorexigenic neuropeptide and, despite many efforts, its receptor has not yet been identified. We found CART peptide specific binding sites in pheochromocytoma PC12 cells. Cells differentiated to neurons increased significantly the number of binding sites. On the other hand, after differentiation to chromaffin cells the number of binding sites was so low that it was impossible to determine their density. To clarify the importance of each of the three disulfide bridges in the CART molecule, analogs with one or two disulfide bridges were synthetized. The biological activity was maintained in analog with two disulfide bridges in positions 74-94 and 88-101. Moreover, we demonstrated the stimulation of JNK and subsequently c-Jun activation in PC12 cells. Neuropeptide PrRP belongs to the RF-amide peptide family and has anorexigenic properties. PrPR has a high affinity to GPR10 and neuropeptide FF (NPFF2) receptor. In our laboratory lipidized analogs of PrRP were synthesized, which are able to decrease food intake after peripheral administration and may cross the blood-brain barrier. We tested biological...