P³² uptake in DNA nucleotides after partial hepatectomy and after unilateral nephrectomy

¹ Endocrine Laboratories, Scripps Clinic and Research Foundation, La Jolla, California

Deoxyribonucleic acid (DNA) synthesis as reflected in the specific activity of DNA nucleotides 12 hr after intraperitoneal injection of P³² has been compared after partial hepatectomy and after unilateral nephrectomy. Thirty-six hours after partial hepatectomy, a maximum uptake 11-fold greater than in controls was found. The maximum after unilateral nephrectomy occurred 48 hr after operation and was twofold greater than in controls. Subsequent to these maxima, P³² uptake declined after both operations to a minimum eight days postoperatively which was followed by a second rise on the 9th day. These data support the concept that similar basic mechanisms regulate growth and cell division after the two types of operation. In another experiment, P³² uptake in kidney DNA nucleotides showed no increase after partial hepatectomy; this lends weight to the hypothesis that the mitosis-stimulating substances which appear in the serum after partial hepatectomy and after unilateral nephrectomy are organ specific.