Induction of mRNAs for heat shock proteins in livers of rats after ischemia and partial hepatectomy.

When the body temperature of rats is elevated to 42 degrees C, four heat shock proteins, with the molecular weights of 70,000, 71,000, 85,000, and 100,000 (hsp 70, hsp 71, hsp 85, and hsp 100, respectively), are induced in various tissues of rats (Fujio et al., J Biochem 101, 181-187, 1987). Heat shock proteins are induced by various stresses other than heat in varieties of cultured cells, so we studied whether heat shock proteins are induced in intact rats by different treatments. Analysis of the translation products of poly(A) + RNA isolated from the livers of rats recovering from ischemia of the liver showed that mRNAs for hsp 70, hsp 71, and hsp 85 were induced. These hsp-mRNAs were also induced in the livers of rats 6 h after a partial hepatectomy, and had returned to control levels 24 h after the surgery. These results suggested that heat shock proteins have not only the function of protection against various stresses but also physiological functions in the normal growth and development of animals.