Hypophysectomy delays the beginning of DNA synthesis in the liver after partial hepatectomy by 15 hr as compared with normal animals. The extended presynthetic period is marked by a continuous rise of RNA and protein synthesis activities, which are preceded by a short, steep upsurge 2 hr after partial hepatectomy. As in the normal animal, the maximum of RNA and protein synthesis immediately precedes the onset of DNA synthesis. A strict topographic correlation can be demonstrated by autoradiography between the RNA synthesis peak and DNA synthesis. After the conclusion of the extended presynthetic phase, the number of parenchymal liver cells synthecizing DNA attains in the hypophysectomized animal the same order of magnitude as is seen in normal partially hepatectomized rats.

1

Part of this work was done at the Rockefeller University, New York, during the tenure of an Eleanor Roosevelt Cancer Fellowship of the American Cancer Society awarded (to H. M. R.) by the International Union Against Cancer. The work was supported by a grant, Ra 101/3,6, from the German Research Association (Deutsche Forschungsgemeinschaft).

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©1969 American Association for Cancer Research.
1969
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