EFFECT OF LONG-CHAIN FATTY-ACIDS ON TRIGLYCERIDE ACCUMULATION, GLUCONEOGENESIS, AND UREAGENESIS IN BOVINE HEPATOCYTES

A relationship between increased lipid concentration in the Liver and reduced hepatic function has been suggested; however, there is little direct evidence of change in specific hepatic functions. Hepatocytes w ere obtained from ruminating calves and were incubated as monolayers f or 36 h. The media contained a mixture of nonesterified fatty acids (N EFA) at 0, 0.5, 1.0, and 1.5 mM NEFA with molar proportions of 0.435 o leate, 0.319 palmitate, 0.144 stearate, 0.049 linoleate, and 0.053 pal mitoleate. Ureagenesis or gluconeogenesis was measured from 48 to 51 h after plating using hepatocytes that had only previous (12 to 48 h), only concurrent (48 to 51 h), or previous and concurrent (12 to 51 h) exposure to NEFA. A previous 36-h exposure to NEFA caused cell triglyc eride accumulation, yielding triglyceride concentrations that correspo nded with liver that is clinically described as normal to moderately f atty. Previous, prolonged exposure to NEFA reduced ureagenesis and inc reased gluconeogenesis. Concurrent exposure to NEFA did not significan tly affect gluconeogenesis or ureagenesis and did not alter the residu al effect of prolonged incubation with NEFA. Reduced ureagenesis was r elated to increased cell triglyceride accumulation independently of ot her direct NEFA effects. Decreased ureagenic capacity may play a role in the morbidity associated with periparturient fatty liver in dairy c ows.