Fig.5 Humoral factors were responsible for the stimulatory action of metformin on thymidine uptake.

Thymidine uptake(DNA synthesis) activity of Ishikawa cells is measured in the presence of serum collected from patients before and during metformin treatment. Serum samples during metformin treatment were collected before and 2 h after a 75 g oral glucose tolerance test. Connecting lines represent paired samples obtained from the same patients. OGTT, oral glucose tolerance test; N.S., not significant. From Mitsuhashi et al., modified with permission^［21］