title: Turnover and short-term regulation of fatty acid binding protein in liver.
abstract: Rat hepatic fatty acid binding protein (hFABP) may play an important role in the intracellular transport and metabolism of fatty acids. Recent reports have suggested a substantial circadian variation in the amount of hFABP in liver, and a half-life of less than 2 h for this protein has been inferred. In the present study, the kinetics of hFABP turnover were examined directly. hFABP half-life measured after pulse labeling with NaH14CO3 was 3.1 days compared with 2.9 days for total cytosol protein. Following double-isotope labeling, the charge isoforms of hFABP showed similar rates of turnover, all of which were slower relative to whole cytosol protein turnover. Following a 48-h fast, total liver hFABP measured by immunoassay fell 65%, paralleling a 60% fall in total cytosol protein. Refeeding for 24 h did not lead to a significant recovery of either hFABP or total cytosol protein content. No significant change was observed in hFABP abundance between mid-light and mid-dark periods of a 24-h light-dark cycle. These studies showed that hFABP has a relatively slow rate of turnover and that it is not acutely modulated by dietary or diurnal influences.
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D002852:Chromatography, Ion Exchange; D002940:Circadian Rhythm; D003600:Cytosol / Q000378:metabolism; D005215:Fasting; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005502:Food; D006207:Half-Life; D008099:Liver / Q000378:metabolism*; D008297:Male; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D009929:Organ Size; D011506:Proteins / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D002352:Carrier Proteins; C490174:Fabp7 protein, rat; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D011506:Proteins