Primary cultures of isolated sheep hepatocytes were used to characterize metabolic functions of liver: gluconeogenesis, ureagenesis and protein synthesis. The rates of all three metabolic activities were linear over a 20 hr culture period. 2. Hepatocytes in the presence of glucagon increased the synthesis of urea by approx 30% (P < 0.05) and increased release of glucose into the medium by 60% (P < 0.05). 3. In the absence of insulin, significantly more (35%; P < 0.05) glucose was released in the medium than in the presence of insulin. 4. Results help evaluate the primary culture of sheep hepatocytes as an appropriate experimental model to study nutritional and hormonal regulation of liver in the ruminant species.