Activation of the glucose-regulated gene (grp78) in regenerating rat liver is nonspecific and is related to acute phase response.

The expression pattern of the hsp70 gene family during regeneration or rat liver has been investigated. Northern blots were prepared from total RNA isolated from livers at 0 h (control), 12 h (end of prereplication phase), 24 h (maximum of DNA synthesis) and 36 h (postmitotic phase) after partial hepatectomy. Blots were hybridized with probes specific for the hsp70 (heat-inducible), hsc70 (constitutively expressed), hst70 (testis-specific) and grp78 (glucose-regulated) gene. No hsp70 and hst70 gene transcripts have been detected at any time point investigated, and only a low increase of the hsc70 mRNA level has been observed 24 h after surgery. In contrast, a significant accumulation of the transcript coded by the grp78 gene has been detected in liver remnant 12 and 24 h after partial hepatectomy. However, we observed a comparable activation of this gene in livers of sham-operated rats or in rats injected with turpentine to cause sterile inflammation. Our results indicate that the activation of the grp78 gene in liver of wounded rats (partial hepatectomy or sham operation) is presumably a part of acute-phase response.