The uptake of radioactive phosphorus by rat liver following partial hepatectomy

Abstract

Summary o 1. Adult male Holtzman rats were given a single subcutaneous injection of radioactive phosphorus, as NaH 2 P 32 O 4 , at 16 hr., and 1, 3, 5, 7, or 14 days after partial hepatectomy. The animals were sacrificed 4 hr. after injection, and the radioactivity and total P content of the acid-soluble organic and inorganic, lipide, phosphoprotein, pentose nucleic acid (PNA), and desoxypentose nucleic acid (DNA) fractions were determined. 2. Following partial hepatectomy there was an increase in the concentration of P per unit of protein N in the acid-soluble inorganic, lipide, PNA, and DNA fractions of the “régenerating” livers. Maximum concentrations were observed at about 1 day in the first two fractions and at 3–5 days in the nucleic acids. Thereafter the concentrations decreased slowly. There were no significant changes in the acid-soluble organic and phosphoprotein P. 3. In the hypertrophying liver cell following partial hepatectomy there was a marked increase in the uptake of P 32 in the acid-soluble organic and inorganic, phosphoprotein, PNA, and DNA fractions over that seen in the controls. With the shift from hypertrophy to cell hyperplasia there was a decline in the P 32 uptake by these fractions. 4. The maximum uptake of P 32 by the phospholipide fraction coincided with maximum mitotic activity.