Photoperiod Regulates vgf-Derived Peptide Processing in Siberian Hamsters

Area of Science:

• Neuroendocrinology
• Seasonal biology

Background:

• VGF mRNA is upregulated in Siberian hamsters during short photoperiods, correlating with appetite loss and weight reduction.
• VGF protein processing yields multiple bioactive peptides with diverse functions.

Purpose of the Study:

• To profile VGF-derived peptides in the brain, pituitary, and plasma of Siberian hamsters.
• To investigate differential VGF peptide processing between short-day (lean) and long-day (fat) states.

Main Methods:

• Immunohistochemistry and ELISA using antisera against proVGF, NERP-1, TPGH, and TLQP peptides.
• Analysis of tissue and plasma VGF peptide levels using HPLC and gel chromatography.

Main Results:

• VGF peptide immunoreactivity was detected in the cortex, hypothalamus, and pituitary.
• Short photoperiods decreased VGF immunoreactivity in the cortex, hypothalamus, and pituitary, but not plasma.
• Multiple VGF-derived peptides and the VGF precursor were identified in various tissues.

Conclusions:

• VGF-derived peptides exhibit pleiotropic effects influenced by photoperiod changes.
• These peptides may regulate cholinergic systems, vasopressin pathways, and the reproductive axis in response to seasonal cues.