Hepatic calcium-binding protein regucalcin in released into the serum of rats administered orally carbon tetrachloride.

The change in calcium-binding protein regucalcin, mainly localized in liver, in the liver and serum of rats received a single oral administration of carbon tetrachloride (50%; 1.0 ml/100 g body weight) was investigated. The change of regucalcin mRNA levels in the liver was analyzed by Northern blotting using liver regucalcin cDNA (0.6 kb). At 10 and 24 h after the administration, liver regucalcin mRNA levels were reduced markedly. Moreover, regucalcin concentrations in the liver and serum was estimated by enzyme-linked immunoadsorbent assay (ELISA) with rabbit-anti-regucalcin IgG. Administration of carbon tetrachloride (CCl4) induced a significant decrease in liver regucalcin concentration and a corresponding elevation of serum regucalcin concentration at 24 h after the administration. An appreciable increase in serum regucalcin concentration was seen at 2 h after the administration. Meanwhile, serum transaminases (GOT and GPT) activities were significantly increased by CCl4 administration, indicating that liver injury is induced. The present study demonstrates that hepatic regucalcin is released into the serum of rats administered orally CCl4, suggesting that the estimation of serum regucalcin is a useful tool for diagnosis of liver injury.