title: Photoperiod Regulates vgf-Derived Peptide Processing in Siberian Hamsters.
abstract: VGF mRNA is induced in specific hypothalamic areas of the Siberian hamster upon exposure to short photoperiods, which is associated with a seasonal decrease in appetite and weight loss. Processing of VGF generates multiple bioactive peptides, so the objective of this study was to determine the profile of the VGF-derived peptides in the brain, pituitary and plasma from Siberian hamsters, and to establish whether differential processing might occur in the short day lean state versus long day fat. Antisera against short sequences at the C- or N- termini of proVGF, as well as against NERP-1, TPGH and TLQP peptides, were used for analyses of tissues, and both immunohistochemistry and enzyme linked immunosorbent assay (ELISA) coupled with high-performance liquid (HPLC) or gel chromatography were carried out. VGF peptide immunoreactivity was found within cortex cholinergic perikarya, in multiple hypothalamic nuclei, including those containing vasopressin, and in pituitary gonadotrophs. ELISA revealed that exposure to short day photoperiod led to a down-regulation of VGF immunoreactivity in the cortex, and a less pronounced decrease in the hypothalamus and pituitary, while the plasma VGF levels were not affected by the photoperiod. HPLC and gel chromatography both confirmed the presence of multiple VGF-derived peptides in these tissues, while gel chromatography showed the presence of the VGF precursor in all tissues tested except for the cortex. These observations are consistent with the view that VGF-derived peptides have pleiotropic actions related to changing photoperiod, possibly by regulating cholinergic systems in the cortex, vasopressin hypothalamic pathways, and the reproductive axis.
authors.affiliation: NEF-Laboratory, Dept. of Biomedical Sciences, University of Cagliari, Monserrato (CA), Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Noli
authors.affiliation: NEF-Laboratory, Dept. of Biomedical Sciences, University of Cagliari, Monserrato (CA), Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Brancia
authors.affiliation: NEF-Laboratory, Dept. of Biomedical Sciences, University of Cagliari, Monserrato (CA), Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Pilleri
authors.affiliation: NEF-Laboratory, Dept. of Biomedical Sciences, University of Cagliari, Monserrato (CA), Italy.
authors.forename: Filomena
authors.initials: F
authors.lastname: D'Amato
authors.affiliation: Department of Life and Environmental Sciences, University of Cagliari, Monserrato (CA), Italy.
authors.forename: Irene
authors.initials: I
authors.lastname: Messana
authors.affiliation: Department of Life and Environmental Sciences, University of Cagliari, Monserrato (CA), Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Manconi
authors.affiliation: School of Life Sciences, University of Nottingham Medical School, Nottingham, United Kingdom.
authors.forename: Francis J P
authors.initials: FJ
authors.lastname: Ebling
authors.affiliation: NEF-Laboratory, Dept. of Biomedical Sciences, University of Cagliari, Monserrato (CA), Italy.
authors.forename: Gian-Luca
authors.initials: GL
authors.lastname: Ferri
authors.affiliation: NEF-Laboratory, Dept. of Biomedical Sciences, University of Cagliari, Monserrato (CA), Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Cocco
mesh_terms: D000818:Animals; D001835:Body Weight / Q000528:radiation effects; D002540:Cerebral Cortex / Q000378:metabolism; D059329:Cholinergic Neurons / Q000378:metabolism; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D006224:Cricetinae; D004797:Enzyme-Linked Immunosorbent Assay; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology; D007031:Hypothalamus / Q000378:metabolism; D008297:Male; D009479:Neuropeptides / Q000502:physiology*; D009929:Organ Size / Q000528:radiation effects; D010446:Peptide Fragments / Q000378:metabolism; D017111:Phodopus / Q000502:physiology*; D017440:Photoperiod; D010902:Pituitary Gland / Q000378:metabolism; D010913:Pituitary-Adrenal System / Q000502:physiology; D011499:Protein Processing, Post-Translational / Q000528:radiation effects*; D012333:RNA, Messenger / Q000096:biosynthesis; D013737:Testis / Q000502:physiology
chemical_list: D009479:Neuropeptides; D010446:Peptide Fragments; D012333:RNA, Messenger; C522413:VGF peptide