Stearyl-CoA desaturase activity in cultured rat hepatocytes.

Stearyl-CoA desaturase activity was measured as a function of time in culture in rat primary hepatocytes up to 90 h of culture. A decrease to half of the original activity occurred within 40 h of culture. Activity remained constant thereafter. Stearyl-CoA desaturase activity increased with insulin molarity in the medium and remained constant as dexamethasone or triiodothyronine concentrations were increased in the medium. When fructose replaced glucose in the medium, the desaturase activity was enhanced. No stimulating effect of cholesterol on the enzyme activity was observed and no inhibiting effect of griseofulvin was shown. Finally, starvation (48 h) of the donor rat followed by 60% sucrose refeeding (48 h) did not enhance delta 9-desaturase activity in the cultured hepatocytes compared with ad libitum nutritional status.