Beneficial effect of nicotinamide on the hyperglycemia in diabetic mice. Recipients received 250 (A, B), 300 (C, D), 350 (E, F), or 400 (G) syngeneic islets that were pretreated without (A, C, E, G) or with (B, D, F) nicotinamide. Individual lines represent the non-fasting plasma glucose levels of each animal. NIC, nicotinamide.