The capacity of urea-N synthesis as a quantitative measure of the liver mass in rats

The capacity of urea-N synthesis (CUNS), the galactose elimination capacity (GEC) and the antipyrine clearance (APC) were measured in rats immediately after 30, 70 and 90% partial hepatectomy and after sham operation. CUNS was assessed during alanine infusion as urea accumulation in total body water, corrected for intestinal hydrolysis, and GEC was measured during constant galactose infusion in the same animals. APC was determined by the one-sample method in a separate group of animals, treated similarily. CUNS, GEC and APC were all correlated to the liver weight with correlation coefficients (r) above 0.8 and the correlation coefficients (r) between CUNS, GEC and APC were all above 0.7. It is concluded that CUNS is a quantitative measure of the functional liver mass in the rat.