Quantification of VGF- and pro-SAAS-derived peptides in endocrine tissues and the brain, and their regulation by diet and cold stress

Brain Res. 2006 May 17;1089(1):21-32. doi: 10.1016/j.brainres.2006.02.124. Epub 2006 May 2.

Abstract

Two novel granin-like polypeptides, VGF and pro-SAAS, which are stored in and released from secretory vesicles and are expressed widely in nervous, endocrine, and neuroendocrine tissues, play roles in the regulation of body weight, feeding, and energy expenditure. Both VGF and pro-SAAS are cleaved into peptide fragments, several of which are biologically active. We utilized a highly sensitive and specific radioimmunoassay (RIA) to immunoreactive, pro-SAAS-derived PEN peptides, developed another against immunoreactive, VGF-derived AQEE30 peptides, and quantified these peptides in various mouse tissues and brain regions. Immunoreactive AQEE30 was most abundant in the pituitary, while brain levels were highest in hypothalamus, striatum, and frontal cortex. Immunoreactive PEN levels were highest in the pancreas and spinal cord, and in brain, PEN was most abundant in striatum, hippocampus, pons and medulla, and cortex. Since both peptides were expressed in hypothalamus, a region of the brain that controls feeding and energy expenditure, double label immunofluorescence studies were employed. These demonstrated that 42% of hypothalamic arcuate neurons coexpress VGF and SAAS peptides, and that the intracellular distributions of these peptides in arcuate neurons differed. By RIA, cold stress increased immunoreactive AQEE30 and PEN peptide levels in female but not male hypothalamus, while a high fat diet increased AQEE30 and PEN peptide levels in female but not male hippocampus. VGF and SAAS-derived peptides are therefore widely expressed in endocrine, neuroendocrine, and neural tissues, can be accurately quantified by RIA, and are differentially regulated in the brain by diet and cold stress.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / anatomy & histology
  • Brain / metabolism*
  • Brain / physiopathology
  • Cold Temperature / adverse effects
  • Dietary Fats / adverse effects
  • Disease Models, Animal
  • Energy Intake / physiology*
  • Feeding Behavior / physiology*
  • Female
  • Food, Formulated / adverse effects
  • Hippocampus / anatomy & histology
  • Hippocampus / metabolism
  • Hippocampus / physiopathology
  • Hypothalamus / anatomy & histology
  • Hypothalamus / metabolism
  • Hypothalamus / physiopathology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Nerve Tissue Proteins / chemistry
  • Nerve Tissue Proteins / metabolism*
  • Neurons / metabolism
  • Neuropeptides / chemistry
  • Neuropeptides / metabolism*
  • Organ Specificity
  • Pancreas / metabolism
  • Pancreas / physiopathology
  • Peptides / analysis
  • Peptides / metabolism
  • Radioimmunoassay / adverse effects
  • Sex Characteristics
  • Stress, Physiological / etiology
  • Stress, Physiological / metabolism*
  • Stress, Physiological / physiopathology
  • Up-Regulation / physiology

Substances

  • Dietary Fats
  • Nerve Tissue Proteins
  • Neuropeptides
  • Pcsk1n protein, mouse
  • Peptides
  • Vgf protein, mouse