EFFECTS OF GROWTH HORMONE ON NUCLEIC ACID AND PROTEIN CONTENT OF RAT LIVER CELLS1

Abstract

Within a given class of ploidy, hypophysectomy did not alter the DNA content per nucleus. Treatment of hypophysectomized rats with a growth hormone preparation resulted in an early, transient increase in DNA per nucleus, followed by a return to control levels. The diploid to tetraploid ratios of nuclei of the liver cells in hypophysectomized rats were larger than those found in control animals and the distribution pattern of diploid to tetraploid was restored to control levels by growth hormone administration. Both nuclei and cytoplasm of liver cells of hypophysectomized rats showed (1) lower protein values, (2) less RNA, and (3) smaller volumes than did those of control rats. Growth hormone treatment of hypophysectomized rats quickly restored nuclear levels of these parameters to those found in controls by cyto-plasmic levels tended to lag during the time period of this study.