Effects of glucagon, insulin, and the eel serum on protein, glycogen, and gluconeogenesis in the eel liver cells in primary culture were investigated. The cells cultured in the medium with 0.25μM glucagon for 6 days synthesized glucose and glycogen from ¹⁴C-pyruvate by 37 and 2.5 times higher respectively, than the control cells cultured without glucagon. Furthermore the cells cultured with glucagon incorporated ¹⁴C-leucine into intracellular and extracellular proteins by 1.6 and 1.3 times higher respectively, than the control cells. However, glucagon inhibited glycogen and protein synthesis from ¹⁴C-glucose remarkably.
The cells cultured with 0.25μM insulin for 6 days inhibited gluconeogenesis from ¹⁴C-pyruvate by 30%, but stimulated glycogen synthesis from ¹⁴C-glucose by 2.3 times compared to the control cells.
The cells cultured in the medium containing 10% eel serum (13.5 mg protein/ml) for 5 days incorporated ¹⁴C-pyruvate into glucose by 100 times higher than the cells cultured with NU-serum, which is an artificial serum. Glycogen synthesis from ¹⁴C-pyruvate was stimulated, but that from ¹⁴C-glucose was not stimulated by the cells cultured with the eel serum. These results showed that the effects of the eel serum resembled those of glucagon, and it is suggested that the eel serum contains something like glucagon.