G6PC1 and Insulin resistance: The same group also showed that catalpol (10–180 μM) prevented insulin resistance induced by glucosamine in cultured HepG2 cells, in which catalpol inhibited the expression of PEPCK and G6pase and increased FOXO1 phosphorylation at Ser256; as in vivo, catalpol inhibited gluconeogenesis and increased glycogen synthesis in this in vitro model of insulin resistance.