Increased insulin-like growth factor binding protein-4 expression after partial hepatectomy in the rat

The insulin-like growth factor (IGF) binding proteins: (IGFBPs) are important regulators of cell growth produced by different tissues. The IGFBPs regulate cell growth by modulating the activity and bioavailability of IGFs. The evidence that IGFBP-1 is a liver-specific immediate-early gene highly induced after 70% partial hepatectomy (PHx) suggests a role for the IGF-IGFBP system in; hepatic regeneration;In this work we analyzed the effect of PHx on the expression of IGFBP-4 which is highly produced by the liver and very abundant in rat serum. Our results show a marked increase in hepatic IGFBP-4 mRNA levels 6-12 h after PHx and no significant change in sham-operated control animals. A parallel rise in IGFBP-4 transcript abundance was observed in the kidneys of PHx rats but not in sham-operated animals. Moreover, ligand blot analysis demonstrated that serum IGFBP-4 levels began to increase 12-24 h after surgery, consistent with the rise in the corresponding mRNA. This enhancement in IGFBP-4 production after PHx could be: part of st fine regulatory mechanism to modulate IGF activity during liver regeneration.