DNA content and size of cell nuclei in the regenerating rat liver

The DNA content in single nuclei and the size of the nuclei were investigated in the intact and regenerating rat liver from 18 h to 21 days after partial hepatectomy. The results of the measurements show that the mean DNA content per nucleus in the intact rat liver is 6.5 pg, and that most nuclei are about equal in size to the diploid nucleus (42.5 ²). DNA synthesis began in the regenerating liver before 18 h after the operation. By 24 h the DNA content in most nuclei of the experimental animals was twice that in the intact rats. This shows that the first wave of synthesis involved 85–90% of the liver cells. After mitosis, which in most cells took place before 36 h after partial hepatectomy weaker waves of DNA synthesis followed, after approximately 42 and 60 h.Department of Normal Anatomy and Department of General Biology, P. J. Safarik University, Kosice, Czechoslovakia. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 8, pp. 369–371, March, 1977.