Cell culture media for mammalian cells

A method of producing recombinant pancreatic islet cells expressing a heterologous gene comprising:

• producing pancreatic islet cells in vitro without serum by introducing pancreatic islet cells into a cell culture medium in vitro, said culture medium comprising 1-150 mg/L arginine;
• 1-120 mg/L proline;
• 1-3050 mg/L nicotinamide;
• 0.1-100 mg/L transferrin chelated with iron;
• greater than 1011 M insulin or insulin-like growth factors;
• 10-12 M-10-3 M glucocorticoid steroid;
• 1-6000 μg/L zinc salt;
• 1-250 μg/L manganese salt;
• 1-1000 μg/L copper salt;
• 1-150 μg/L selenium salt;
• 2.0-10.0 mM L-glutamine;
• 0.01-5.0 g/L D-galactose or 0.01-5.0 g/L D-glucose, or when both D-galactose and D-glucose are included together, 0.01-8.0 g/L, and culturing said introduced cells in said medium;
• and
• transforming said cultured pancreatic islet cells with a nucleic acid capable of expressing said gene in said cells.