Effects of hormones on the activity of glucose-6-phosphatase in primary cultures of rat hepatocytes

Although the activity of glucose-6-phosphatase in rat liver is altered markedly following the administration of a variety of hormones in vivo, it is not certain whether the hormones act directly on the hepatocyte. To study this problem hepatocytes were isolated by a collagenase-perfusion technique and cultured on collagen gel/nylon mesh membranes. The activity of glucose 6-phosphatase in cells cultured with fetal calf serum and with Dulbecco's modified Eagle's medium or Leibovitz L-15 medium decreased to less than 10-30% of the activity in freshly isolated cells by 96 h. However, when L-15 plus newborn or fetal calf serum was supplemented with glucagon (10(-6)M), epinephrine (10(-6)M), triiodothyronine (10(-6)M), and dexamethasone (10(-5)M) (L-15-GETD), the activity of glucose-6-phosphatase was maintained so that, after 144 h, the activity was at least 80% of that detected in freshly isolated cells. In cells cultured in L-15 plus serum for 72 or 96 h and then in L-15-GETD, glucose-6-phosphatase increased 30-50% over that in control cultures after 24 h. Insulin, which decreases glucose-6-phosphatase activity when administered to intact animals, also decreased the glucose-6-phosphatase activity in cultured hepatocytes to 20-50% of that in controls.